Polycyclic Agents for the Treatment of Respiratory Syncytial Virus Infections

ABSTRACT

Compounds of formula (I), and their use as in the treatment of infections involving viruses of the Pneumovirinae sub-family (RSV) are disclosed. In the formula ring (A) may be phenyl, pyridyl etc., (B-C) may be CH 2 —CH 2  etc., (R 1 ) may be phenyl and substituted forms thereof, (R 2 ) may be assorted substituents.

FIELD OF THE INVENTION

The present invention relates to antiviral compounds, methods for their preparation and compositions containing them, and use at the compounds and composition in the treatment of viral infections. In particular, the invention relates to the use of compounds of formula I for the treatment of respiratory syncytial virus infection.

BACKGROUND ART

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infection in adults and in young children. In the western world approximately all children have been infected by the age of two. In most cases the RSV infections will only cause minor upper respiratory illness with symptoms resembling that of the common cold. However, severe infection with the virus may result in bronchiolitis or pneumonia which may result in hospitalization or death. Infants who have been born prematurely or have a pre-existing lung disease are a high risk of severe infection and complications.

Respiratory syncytial virus (RSV) is a member of the order Mononegalirales, which consists of the non-segmented negative strand RNA viruses in the Families Paramyxoviridae, Rhabdoviridae and Filoviridae. RSV of humans (often termed RSV or HRSV) is a member of the Pneumovirus genus of the sub-family Pneumovirinae within the Family Paramyxoviridae. Other members of the Pneumovirus genus include viruses such as bovine RSV (BRSV), ovine RSV (ORSV) and murine pneumonia virus (MPV) amongst others. The sub-family Pneumovirinae also includes the genus Metapneumovirus which contains the recently identified and important human pathogen human metapneumovirus.

In addition to the genome features described above, Family characteristics include a lipid envelope containing one or more glycoprotein species considered to be associated with attachment and entry of the host cell. Entry is considered to require a process by which the viral envelope fuses with the membrane of the host cell. Fusion of infected cells with, for example, their neighbours, can also result in the formation of fused multinucleate cells known as syncytia in some cases. The fusion process is believed to be glycoprotein mediated and is a feature shared with diverse enveloped viruses in other taxonomic groups. In the case of the Paramyxovrldae viruses of all genera characteristically express a fusion glycoprotein (F) which mediates membrane fusion

The only drug currently approved for the treatment of severe RSV is the antiviral medication, Virazole, also known as Ribavirin. This agent has a broad spectrum antiviral with virustatic effects, and acts by inhibiting RSV replication. It also improves arterial blood oxygenation. Unfortunately, the agent is toxic so that administration of the agent is confined to a hospital setting. Its administration is further complicated by the need to follow a strict procedural process when administering the agent in order to minimise the likelihood of certain adverse affects. The agent has a number of adverse effects including sudden deterioration of respiratory function (bronchiospasm). The efficacy of the agent has remained controversial and thus there is a real need to find an alternative agent for the treatment of RSV infection.

A number of agents are known to inhibit RSV. Published patent applications WO 01/95910 and WO 02/26228 (Bristol Myers Squib Company), the contents of which are incorporated by cross reference, describe a number of different types of compounds which exhibit anti-RSV activity in their description of the background art. Moreover, these applications describe compounds having antiviral activity against RSV of the formula

There are also a number of patent specifications that disclose imidazo-[2,1-a]-isoindole derivatives for uses other than treating RSV. U.S. Pat. No. 3,507,863 describes a number of polycyclic compounds that have anti-inflammatory and anti-convulsive activity. These compounds have the following general structure

where A is —NH—, —O— or —S—, and n is 1-3.

U.S. Pat. No. 3,770,766 describes polycyclic compounds that have antidepressant activity, and have the following general structure

where R₃ is selected from various aromatic substituents.

U.S. Pat. No. 4,058,529 discloses anti-inflammatory and anti-convulsive activity polycyclic compounds of the general formula A, and includes compounds of the formula B where R₂ is hydrogen or lower alkyl group (including amino substituted groups) and n is 1-3.

CH 482,697 (Graf) discloses a number of compounds of the general formula B above, where R₂ is —CO—CHR—N₃ and R is hydrogen or alkyl, and intermediates where R₂ is —CO—CHR—NH₂, —CO—CHR—OH or hydrogen. Likewise U.S. Pat. No. 3,590,043 (Graf) relates to compounds of the formula B where R₂ is —CO—CHR—NR′R″. In this document n is 1 to 3, R is H or lower alkyl, R′ and R″ may be lower alkyl or benzyl or together form a piperidinyl or morpholinyl ring. The Graf compounds may have anti-inflammatory uses.

WO 02/066479 (Banyu Pharmaceutical) lists some compounds of the general formula B, where R₂ is lower alkyl, —CO—C₂H₅ and selected other moieties. It also appears to suggest a compound of formula B where the fused phenyl ring has been replaced with pyridyl and R₂ is methyl. It is not clear whether all of these compounds have been made. The compounds are for use in the treatment of high blood pressure and diabetes.

GB 1,038,735 discloses anti-inflammatory compounds of the general formula B, where n is 1 to 3, R₂ is lower alkyl or, for example, an dimethylaminoethyl group.

Canadian patent application no. 2,108,899 (also see family member WO 92/16207) discloses various oxazolo-[2,3-a]-isoindole and imidazo-[2,1-a]-isoindole derivatives for use in antiviral medicaments, particularly for use in the treatment of AIDS and HIV. There are marked differences between HIV and RSV viruses, the diseases they are associated with, and the respective modes of action of the disclosed compounds. The specification generally describes compounds of the structure below where R is C₁-C₆ alkyl group or C₁-C₆ acyl group, and specifically discloses compounds where R is —COCH₃ or —CH₃.

A number of documents disclose compounds of the above formula or substituted forms thereof, where R is hydrogen. See for example the herbicidal compounds disclosed in U.S. Pat. Nos. 4,726,838 and 4,846,876.

SUMMARY OF THE INVENTION

The invention relates to the discovery that certain compounds exhibit favourable anti-RSV activity by inhibition of the RSV virus's essential fusion processes.

This invention provides for the use of a compound of formula I

its salts, and pharmaceutically acceptable derivatives thereof, in the treatment of respiratory syncytial virus (RSV) infections, wherein R₁ is selected from C₁₋₁₂ alkyl, C₂₋₁₂ alkenyl, C₂₋₁₂ alkynyl, —(CH₂)_(n)C₃₋₇ cycloalkyl, —(CH₂)_(n)C₄₋₇ cycloalkenyl, —(CH₂) aryl, —(CH₂)_(n) arylC₁₋₁₂ alkyl, —(CH₂)_(n) arylC₂₋₁₂ alkenyl, —(CH₂)_(n) arylC₂₋₁₂ alkynyl, and —(CH₂)_(n) heterocyclyl; n is 0-6 and said alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl and heterocyclyl groups are optionally substituted; R₂ is selected from —CH₂R₃, —C(Y)R₃, —C(Y)OR₃, —C(Y)N(R₄)R₃, —C(Y)CH₂N(R₄)R₃, —C(Y)CH₂SR₃ and —S(O)_(w)R₅, where R₃ is selected from hydrogen, C₁₋₁₂ alkyl, C₂₋₁₂ alkenyl, C₂₋₁₂ alkynyl, —(CH₂)_(m)C₃₋₇ cycloalkyl, —(CH₂)_(m)C₄₋₇ cycloalkenyl, —(CH₂)_(m) aryl, —(CH₂)_(m) arylC₁₋₁₂ alkyl, —(CH₂)_(m) arylC₂₋₁₂ alkenyl, —(CH₂)_(m) arylC₂₋₁₂ alkynyl and —(CH₂)_(m) heterocyclyl; and when R₂ is —CH₂R₃, or —C(Y)R₃, R₃ may also be selected from —S—R₅ and —O—R₅; m is 0-6; R₄ is hydrogen or C₁₋₆ alkyl; R₅ is C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, C₃₋₇ cycloalkyl, C₄₋₇ cycloalkenyl, benzyl, aryl or heterocyclyl; w is 0, 1 or 2, and the alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl and heterocyclyl groups are optionally substituted; X and Y are independently selected from O, S and NR₆, where R₆ is independently selected from hydrogen, lower alkyl, hydroxy and lower alkoxy; A together with the atoms to which it is attached, forms an optionally substituted aromatic ring; B-C together with the atoms to which they are attached, forms an optionally substituted heterocyclic ring having from 5 to 8 ring atoms.

The invention also provides for the use of compounds of formula I, its salts, and pharmaceutically acceptable derivatives thereof, in the treatment of RSV infections by the inhibition of the virus's fusion processes.

The invention also provides novel compounds of formula I, their salts, and pharmaceutically acceptable derivatives thereof.

DESCRIPTION OF PREFERRED EMBODIMENTS

As used herein the term “aromatic” refers to aryl rings or ring systems and aromatic heterocyclic rings or ring systems, as known as heteroaryl or heteroaromatic rings.

As used herein the term “aryl” refers to carbocyclic (non-heterocyclic) aromatic rings or ring systems. The aromatic rings may be mono- or bi-cyclic ring systems. The aromatic rings or ring systems are generally composed of 5 to 10 carbon atoms. Examples of suitable aryl groups include but are not limited to phenyl, biphenyl, naphthyl, tetrahydronaphthyl, and the like.

Preferred aryl groups include phenyl, naphthyl, indenyl, azulenyl, fluorenyl or anthracenyl.

The term “heterocyclic” or “heterocyclyl” as used herein refers to mono or bicyclic rings or ring systems that include one or more heteroatoms selected from N, S and O. The rings or ring systems generally include 1 to 9 carbon atoms in addition to the heteroatom(s) and may be saturated, unsaturated or aromatic (including pseudoaromatic). The term “pseudoaromatic”*refers to a ring system which is not strictly aromatic, but which is stabilized by means of delocalization of electrons and behaves in a similar manner to aromatic rings. Aromatic includes pseudoaromatic ring systems, such as furyl, thienyl and pyrrolyl rings.

Examples of 5-membered monocyclic heterocycles include furyl, thienyl, pyrrolyl, H-pyrrolyl, pyrrolinyl, pyrrolidinyl, oxazolyl, oxadiazolyl, (including 1,2,3 and 1,2,4 oxadiazolyls) thiazolyl, isoxazolyl, furazanyl, isothiazolyl, pyrazolyl, pyrazolinyl, pyrazolidinyl, imidazolyl, imidazolinyl, triazolyl (including 1,2,3 and 1,3,4 triazolyls), tetrazolyl, thiadiazolyl (including 1,2,3 and 1,3,4 thiadiazolyls). Examples of 6-membered monocyclic heterocycles include pyridyl, pyrimidinyl, pyridazinyl, pyranyl, pyrazinyl, piperidinyl, 1,4-dioxanyl, morpholinyl, 1,4-dithianyl, thiomorpholinyl, piperazinyl, 1,3,5-trithianyl and triazinyl. The heterocycles may be optionally substituted with a broad range of substituents, and preferably with C₁₋₆ alkyl, C₁₋₆ alkoxy, C₂₋₆ alkenyl, C₂₋₆ alkynyl, halo, hydroxy, mercapto, trifluoromethyl, amino, cyano or mono or di(C₁₋₆alkyl)amino.

The heterocycle may be fused to a carbocyclic ring such as phenyl, naphthyl, indenyl, azulenyl, fluorenyl, and anthracenyl.

Examples of 8, 9 and 10-membered bicyclic heterocycles include 1H thieno[2,3-c]pyrazolyl, thieno[2,3-b]furyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzoxazolyl, benzothiazolyl, benzisoxazolyl, benzisothiazolyl, benzimidazolyl, indazolyl, isoquinolinyl, quinolinyl, quinoxalinyl, uridinyl, purinyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, benzotriazinyl, naphthyridinyl, pteridinyl and the like. These heterocycles may be optionally substituted, for example with C₁₋₆alkyl, C₁₋₆alkoxy, C₂₋₆alkenyl, C₂₋₆alkynyl, halo, hydroxy, mercapto, trifluoromethyl, amino, cyano or mono or di(C₁₋₆alkyl)amino.

Examples of preferred heterocyclic radicals include (optionally substituted) isoxazoles, isothiazoles, 1,3,4-oxadiazoles, 1,3,4-thiadiazoles, 1,2,4-oxadiazoles, 1,2,4-thiadiazoles, oxazoles, thiazoles, pyridines, pyridazines, pyrimidines, pyrazines, 1,2,4-triazines, 1,3,5-triazines, benzoxazoles, benzothiazoles, benzisoxazoles, benzisothiazoles, quinolines and quinoxalines. These heterocycles can be optionally substituted with, by example, with C₁₋₆alkyl, C₁₋₆alkoxy, C₂₋₆alkenyl, C₂₋₆alkynyl, halo, hydroxy, mercapto, trifluoromethyl, amino, cyano or mono or di(C₁₋₆alkyl)amino.

Examples of particularly preferred heterocyclic radicals include furyl, thienyl, pyridyl, oxazolyl, thiazolyl, pyrazolyl, furazanyl, isoxazolyl, isothiazolyl, 1,2,3-triazolyl, 1,3,4-triazolyl, 1,2,3-thiadiazolyl, 1,3,4-thiadiazolyl, pyridazinyl, pyrimidinyl, benzo[b]furanyl, benzo[b]thiophenyl and benzoisoxazolyl.

Examples of unsaturated 5-membered heterocyclic rings include oxazole, thiazole, imidazole, 1,2,3-triazole, isoxazole, isothiazole, pyrazole, furan, thiophene and pyrrole. Examples of unsaturated 6-membered heterocyclic rings include pyridine, pyrimidine, pyrazine, pyridazine and 1,2,4-triazine.

In a preferred embodiment, the heterocyclic ring is an aromatic ring. Heteroaryl and heteroaromatic are used herein to refer to this subset of heterocyclic rings. Heteroaryl rings include furyl, thienyl, pyridyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, 1,2,3-oxadiazolyl, 1,2,4-oxadiazolyl, 1,2,4-oxadiazol-5-one, 1,2,3-triazolyl, 1,3,4-thiadiazolyl, pyridazinyl, pyrimidinyl, pyrazinyl, 1,3,5-triazinyl, 1H thieno[2,3-c]pyrazolyl, thieno[2,3-b]furyl, indolizinyl, indolyl, isoindolyl, 3H-indolyl, indolinyl, benzo[b]furanyl, benzo[b]thiophenyl, 1H-indazolyl, benzimidazolyl, tetrazolyl, uridinyl, and cytosinyl.

More preferably heteroaryl or heteroaromatic is selected from isoxazolyl, oxazolyl, imidazolyl, thiazolyl, thiadiazolyl, isothiazolyl, furazanyl, triazolyl, pyridyl, pyrimidinyl, furyl, pyrazolyl, pyridazinyl, thienyl and aryl fused heteroaromatic rings such as benzfuranyl, benzothiophenyl and benzoisoxazolyl.

In another preferred embodiment, the heterocyclic ring is a non-aromatic ring selected from the group consisting of pyrrolidine, imidazoline, 2-imidazolidone, 2-pyrrolidone, pyrrolin-2-one, tetrahydrofuran, 1,3-dioxolane, piperidine, tetrahydropyran, oxazoline, 1,3-dioxane, 1,4-piperazine, morpholine and thiomorpholine.

The heterocyclic ring containing the linker group B-C may be selected from the above described heterocyclic rings provided the ring meets the requirement of containing at least two nitrogen atoms and excludes aromatic ring systems.

Unless otherwise defined, the term “optionally substituted” as used herein means that a group may include one or more substituents that do not interfere with the binding activity of the compound of formula I. In some instances the substituent may be selected to improve binding. The group may be substituted with one or more substituents selected from halogens, C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, —(CH₂)_(p)C₃₋₇ cycloalkyl, —(CH₂)_(p)C₄₋₇ cycloalkenyl, —(CH₂)_(p) aryl, —(CH₂)_(p) heterocyclyl, —C₆H₄S(O)_(t)C₁₋₆ alkyl, —C(Ph)₃, —(CH₂)_(p)Z, —COZ, —CN, —OR, —O—(CH₂)₁₋₆—R, —O—(CH₂)₁₋₆—OR, —OCOR, —COR, —COOR, —OCONR′R″, —NR′R″, —NRCOR′, —NRCONR′R″, —NRC(S)NR′R″, —NRSO₂R′, —NRCOOR′, —C(NR)NR′R″, —CRNOR′, —C(═NOH)NR′R″, —CONR′R″, —C(═NCN)—NR′R″, —C(═NR)NR′R″, —C(═NR′)SR″, —NR′C(═NCN)SR″, —CONRSO₂R′, —C(S)NR′R″, —S(O)_(t)R, —SO₂NR′R″, —SO₂NRCOR′, —OS(O)₂R, —PO(OR)₂ and —NO₂; where p is 0-6, t is 0-2, Z is an N-linked amino acid selected from the group consisting of alanine, asparagine, aspartic acid, glutamic acid, glutamine, glycine, pipecolic acid, α-amino-butyric acid, α-amino-propanoic acid, and iminodiacetic acid, Z being linked through a nitrogen atom of said N-linked amino acid to the carbon atom, and each R, R′ and R″ is independently selected from H, C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, C₃₋₇ cycloalkyl, C₄₋₇ cycloalkenyl, aryl, heterocyclyl, C₁₋₆ alkylaryl abd C₁₋₆ alkylheterocyclyl, wherein the alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, heterocyclyl, C₁₋₆ alkylaryl or C₁₋₆ alkylheterocyclyl, may be optionally substituted with one to six of same or different selected from halogen, hydroxy, lower alkyl, lower alkoxy, —CO₂H, CF₃, CN, phenyl, NH₂ and —NO₂; or when R′ and R″ are attached to the same nitrogen atom, they may, together with the atom to which they are attached, form a 5 to 7 membered nitrogen containing heterocyclic ring.

When the optional substituent is or contains an alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl or heterocyclyl group, the group may itself be optionally substituted with one to six of the same or different halogen atoms, hydroxy, lower alkyl, lower alkoxy, halo-C₁₋₆ alkyl (including —CF₃), phenyl, benzyl, —CN, —C(O)—C₁₋₆ alkyl, mercapto, —NH₂, mono or di (lower alkyl)amino or —NO₂.

In relation to nitrogen containing heterocyclic rings, unless otherwise defined optionally substituted includes pyridinium salts and the N-oxide form of suitable ring nitrogens.

In relation to non-aromatic carbocyclic or heterocyclic compounds, unless otherwise defined such compounds may also be optionally substituted with one or two ═O groups, instead of or in addition to the above described optional substituents.

Examples of optional substituents include halogens, C₁₋₄ alkyl, C₂₋₄ alkenyl, C₂₋₄ alkynyl, C₁₋₄ alkoxy, C₁₋₄ haloalkyl, —CF₃, —OH, phenyl, —NH₂, —NHC₁₋₄ alkyl, —N(C₁₋₄)₂, —CN, mercapto, C₁₋₄ alkylcarbonyl and C₁₋₄ alkoxycarbonyl.

As used herein the term “C₁₋₁₂ alkyl” refers to straight chain or branched saturated hydrocarbon group having from 1 to 12 carbon atoms. Examples of such alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl. Similarly “C₁₋₆ alkyl” or “lower alkyl” refers to such groups having from 1 to 6 carbon atoms.

As used herein the term “C₃₋₇ cycloalkyl” refers to non-aromatic, saturated cyclic groups having from 3 to 7 carbon atoms. Examples include cyclopentyl and cyclohexyl.

As used herein the term “alkoxy” refers to a straight or branched alkyl group covalently bound via an O linkage and the terms “C₁₋₄ alkoxy” and “lower alkoxy” refer to such groups containing from one to six carbon atoms, such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, t-butoxy and the like.

As used herein the term “C₂₋₁₂ alkenyl” refers to groups formed from C₂₋₁₂ straight chain or branched non-cyclic hydrocarbon containing one or more double bonds. Examples of C₂₋₁₂ alkenyl include allyl, 1-methylvinyl, butenyl, iso-butenyl, 1,3-butadienyl, 3-methyl-2-butenyl, 1,3-butadienyl, 1,4-pentadienyl, 1-pentenyl, 1-hexenyl, 3-hexenyl, 1,3-hexadienyl, 1,4-hexadienyl and 1,3,5-hexatrienyl.

As used herein the term “C₄₋₇ cycloalkenyl” refers to non aromatic carbocycles having 4 to 7 carbon atoms and having one or more double carbon bonds. Examples include cyclopentenyl, 1-methyl-cyclopentenyl, cyclohexenyl, 1,3-cyclopentadienyl, 1,3-cyclohexadienyl and 1,4-cyclohexadienyl.

As used herein the term “C₂₋₁₂ alkynyl” refers to C₂₋₁₂ straight or branched non-cyclic hydrocarbon containing one or more triple bonds, preferably one or two triple bonds. Examples include 2-propynyl and 2- or 3-butynyl.

The term “aryl C₁₋₁₂ alkyl” refers to carbocyclic aromatic rings or ring systems as previously described and substituted by a C₁₋₁₂ alkyl group, also as previously described.

Likewise the terms “aryl C₂₋₁₂ alkenyl” and “aryl C₂₋₁₂ alkynyl” refer to carbocyclic aromatic rings or ring systems as previously described and substituted by a C₂₋₁₂ alkenyl or C₂₋₁₂ alkynyl group, as previously described.

The aryl group and the alkyl, alkenyl or alkynyl group may be optionally substituted. Preferably the aryl group is not optionally substituted.

Preferably the alkyl, alkenyl or alkynyl group is optionally substituted, and more preferably with a substituent selected from halogens, —CN, —NR′R″, —COR, —COOR, or —CONR′R″. Preferably R, R′ and R″ are independently selected from hydrogen or lower alkyl.

As used herein the term “halo” or “halogen” refers to fluoro, chloro, bromo and iodo groups.

As used herein a “halo alkyl” group has one or more of the hydrogen atoms on an alkyl group replaced with halogens. An example includes —CF₃.

Particularly preferred compounds of the invention include those compounds where A is a bivalent link of 3 or 4 atoms selected from C, N, O and S. In that arrangement A and the atoms to which they are attached together form an aromatic ring having five or six ring atoms. When the linking atoms are all carbon, the ring formed is a carbocyclic aromatic ring or ring system. When the linking atoms include one or more of N, O or S then the ring formed is an aromatic heterocyclic ring. Examples include where the substructure

is:—

Preferably ring A is an optionally substituted aryl or heteroaryl ring, more preferably a phenyl, pyridyl, pyridazinyl, pyrimidinyl or pyrazinyl ring, and most preferably a phenyl or pyridyl ring. The optionally substituents include N-oxides of the ring nitrogen atoms.

The aromatic rings may be optionally substituted, preferably by no more than 3 substituents. Of the optional substituents, it is particular preferred to use 1 to 3 substituents selected from halo, lower alkyl, halogenated forms of lower alkyl, hydroxy, lower alkoxy, nitro, amino, loweralkylamino, carboxy, carboxamido, phenyl and benzyl. N-oxide forms of the nitrogen atoms of nitrogen containing rings are also preferred. When A is a pyridyl ring, the ring nitrogen may be in a N-oxide form, or the ring may be in the form of a pyridinium salt.

In respect of the heterocyclic ring formed by B-C, it will be understood that this ring can not be selected from all of the heterocyclic rings discussed earlier in relation to the meaning of the term due to the atoms to which B-C are attached. This ring is limited to monocyclic, non-aromatic heterocyclic rings that include at least two nitrogen atoms. The ring may include additional hetero atoms and may be partially unsaturated.

Particularly preferred are compounds in which B-C represents a bivalent link of 1 to 3 atoms. The link B-C together with the atoms to which it is attached forms a non-aromatic heterocyclic ring. Examples include where the substructure:—

In a preferred form of the invention, B-C represents —CH₂—(CH₂)_(z)—, where z is 1-4, more preferably 1, 2 or 3, more preferably 1 or 2 and most preferably z is 1.

The atoms forming the link B-C may be optionally substituted, preferably by no more than 3 substituents. A broad range of substituents are possible and include halo, lower alkyl, hydroxy, lower alkoxy, phenyl and benzyl.

A preferred form of the invention includes those compounds where B-C represents —CH₂CH₂—.

Preferably X is oxygen or sulphur, more preferably X is oxygen.

In an embodiment of the invention fused ring A and the ring containing the bivalent link B-C are optionally substituted with one or two substituents independently selected from halogen and C₁₋₆ alkyl. Preferably fused ring A and the ring containing the bivalent link B-C are not substituted.

R₁ may be an optionally substituted aryl, alkyl or heterocyclyl. Preferably R₁ is an optionally substituted aryl or heterocyclyl group, more preferably a phenyl, thienyl, pyrrolyl or pyridyl ring. R₁ may also be a —C₁₋₄ alkylphenyl group. The rings of R₁ may b optional substituted with halo, hydroxy, nitro, —NR′R″ (where R′ and R″ are independently selected from hydrogen, lower alkyl and —C(O)R, where R is C₁₋₆ alkyl, phenyl or heterocyclyl), C₁₋₁₂alkyl, phenyl and —O—R_(a), where R_(a) is —C₁₋₁₂alkyl, —C₃₋₇cycloalkyl, —C₁₋₁₂alkylC₃₋₇cycloalkyl, phenyl or —C₁₋₁₂alkylphenyl; and the C₁₋₁₂alkyl, phenyl or R_(a) group may be optionally substituted with halo, —CN, —NR′R″, —CO₂R or —CONR′R″, where R, R′ and R″ are independently selected from hydrogen or lower alkyl. Preferably, the ring is phenyl and is optionally substituted in the para or 4-position.

R₁ may be -phenyl substituted with C₁₋₁₀ alkyl chain, where the alkyl chain is substituted with halo, —CN, —NR′R″, —CO₂R or —CONR′R″, where R, R′ and R″ are independently selected from hydrogen or lower alkyl. More preferably the alkyl chain is in the 4-position of the phenyl ring, and substituents are attached to the carbon at the free end of the alkyl group.

R₁ may be phenyl optionally substituted with a substituent selected from halo, —C₁₋₆alkyl, —C₁₋₆alkylhalo, —C₁₋₆alkylCN, —OC₁₋₆alkyl, —OC₁₋₆alkylhalo, —OC₁₋₆alkylCO₂NH₂, —OC₁₋₆alkylCN, —OC₁₋₆alkylC₃₋₇cycloalkyl, —OC₁₋₆alkylC₆H₅, —OC₁₋₆alkylOCH₃, —OC₆H₅, —OC₆H₄halo, —CF₃, —OCF₃, —NR′R″ (where R′ and R″ are independently selected from hydrogen, —C(O)C₁₋₆alkyl, —C(O)C₆H₅, —C(O)CH═CHCO₂H, —C(O)C₁₋₆alkylCO₂H, —C(O)C₁₋₆alkylCO₂CH₃, —C(O)C₁₋₆alkylC₆H₅, —C(O)C₁₋₆alkylC₆H₄CH₃, —C(O)C₁₋₆alkylC₆H₄OCH₃ and —C(O)C₁₋₆alkylC₆H₄halo), —CO₂H, —CO₂C₁₋₆alkyl, —NO₂, —OH, —C₆H₅, —C₆H₄C₁₋₆alkyl, —C₆H₄halo and —OC(O)C₁₋₆alkyl.

Preferably R₁ is halophenyl, most preferably 4-chlorophenyl.

Compounds where R₂ is hydrogen do not form part of the present invention. These compounds are useful as intermediates for the production of compounds of the invention in which R₂ is not hydrogen.

Preferably R₂ is not an unsubstituted —C₁₋₆alkyl or unsubstituted —C(O)—C₁₋₆alkyl.

When R₂ is —CH₂—R₃, it is preferred that R₃ is —(CH₂)_(m) aryl or —(CH₂)_(m) heterocyclyl, where m is 0 to 3. R₃ may be benzyl (m=1). The ring atoms may by optionally substituted with a broad range of substituents. Preferred substituents are selected from halo, lower alkyl, hydroxy, lower alkoxy and phenyl.

When R₂ is —C(Y)—R₃, it is preferred that Y is O. It is also preferred that R₃ is —(CH₂)_(m) aryl or —(CH₂)_(m) heteroaryl, where m is 0 to 3. It is particularly preferred for R₃ to be aryl or heteroaryl (m=0), and more preferably a or 6 membered monocyclic heterocycle or 9 or 10 membered bicyclic heterocycle or an aryl group.

When R₂ is —C(Y)CH₂N(R₄)R₃ or —C(Y)CH₂SR₃, R₃ is preferably —(CH₂)_(m) aryl or —(CH₂)_(m) heterocyclyl where m is 0 to 3. The heterocycyl may itself be substituted with an oxo group, hydroxy or lower alkyl.

More preferably R₃ is phenyl, naphthyl, furyl, thienyl, pyrrolyl, H-pyrrolyl, pyrrolinyl, pyrrolidinyl, oxazolyl, oxadiazolyl, (including 1,2,3 and 1,2,4 oxadiazolyls) thiazolyl, isoxazolyl, furazanyl, isothiazolyl, pyrazolyl, pyrazolinyl, pyrazolidinyl, imidazolyl, imidazolinyl, triazolyl (including 1,2,3 and 1,3,4 triazolyls), tetrazolyl, thiadiazolyl (including 1,2,3 and 1,3,4 thiadiazolyls), pyridyl, pyrimidinyl, pyridazinyl, pyranyl, pyrazinyl, piperidinyl, 1,4-dioxanyl, morpholinyl, 1,4-dithianyl, thiomorpholinyl, piperazinyl, 1,3,5-trithianyl, triazinyl, 1H thieno[2,3-c]pyrazolyl, thieno[2,3-b]furyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzoxazolyl, benzothiazolyl, benzisoxazolyl, benzisothiazolyl, benzimidazolyl, indazolyl, isoquinolinyl, quinolinyl, quinoxalinyl, uridinyl, purinyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, benzotriazinyl, naphthyridinyl or pteridinyl.

The heterocyclic ring may be fused to a carbocyclic ring such as phenyl, naphthyl, indenyl, azulenyl, fluorenyl, and anthracenyl.

The aryl or heterocyclic may be optionally substituted with a broad range of substituents, and preferably with C₁₋₆ alkyl, C₁₋₆ alkoxy, C₂₋₆ alkenyl, C₂₋₆ alkynyl, halo, hydroxy, mercapto, trifluoromethyl, amino, nitro, cyano and mono or di(C₁₋₆alkyl)amino. The substituents also include phenyl, benzyl and heterocyclyl.

Most preferably R₃ is selected from phenyl, furyl, thienyl, pyridyl, oxazolyl, thiazolyl, pyrazolyl, furazanyl, isoxazolyl, isothiazolyl, 1,2,3-triazolyl, 1,3,4-triazolyl, 1,2,3-thiadiazolyl, 1,3,4-thiadiazolyl, pyridazinyl, pyrimidinyl, benzo[b]furanyl, benzo[b]thiophenyl and benzoisoxazolyl.

When R₂ is —COR₃, it is also preferred for R₃ to be -phenylC₁₋₁₀ alkyl, where the alkyl is substituted with halo, —CN, —NR′R″, —CO₂R or —CONR′R″, where R, R′ and R″ are independently selected from hydrogen or lower alkyl. More preferably the alkyl chain is in the 4-position of the phenyl ring, and substituents are attached to the carbon at the free end of the alkyl group.

When R₂ is —CON(R₄)R₃ it is preferred for R₄ to be hydrogen and R₃ to be —(CH₂)_(m) aryl or —(CH₂)_(m) heteroaryl. Preferably m is 0 to 2, more preferably 0 to 1. The aryl and heteroaryl ring atoms may be optionally substituted with a broad range of substituents. Preferred substituents include halo, lower alkyl, hydroxy, lower alkoxy and phenyl.

Another preferred embodiment of the invention are those compounds where R₂ is —COR₃ and fused ring A contains at least one ring nitrogen atom.

When the invention relates to compounds of formula I per se, it is preferred that when R₁ is unsubstituted phenyl, X is O, A together with the atoms to which it is attached forms an unsubstituted phenyl ring and B-C is —CH₂CH₂—, R₂ is not unsubstituted C₁₋₆ alkyl or —C(O)C₁₋₆ alkyl.

It will be appreciated that compound of formula I and some derivatives thereof may have at least one asymmetric centre, and therefore are capable of existing in more than one stereoisomeric form. The invention extends to each of these forms individually and to mixtures thereof, including racemates. The isomers may be separated conventionally by chromatographic methods or using a resolving agent. Alternatively the individual isomers may be prepared by asymmetric synthesis using chiral intermediates. Where the compound has at least one carbon-carbon double bond, it may occur in Z- and E-forms and all isomeric forms of the compounds being included in the present invention.

The salts of the compound of formula I are preferably pharmaceutically acceptable, but it will be appreciated that non-pharmaceutically acceptable salts also fall within the scope of the present invention, since these are useful as intermediates in the preparation of pharmaceutically acceptable salts.

The term “pharmaceutically acceptable derivatives” includes pharmaceutically acceptable esters, prodrugs, solvates and hydrates, and pharmaceutically acceptable addition salts of the compounds or the derivatives. Pharmaceutically acceptable derivatives may include any pharmaceutically acceptable salt, solvate, hydrate or any other compound or prodrug which, upon administration to a subject, is capable of providing (directly or indirectly) a compound of formula I or an antivirally active metabolite or residue thereof.

The pharmaceutically acceptable salts include acid addition salts, base addition salts, salts of pharmaceutically acceptable esters and the salts of quaternary amines and pyridiniums. The acid addition salts are formed from a compound of the invention and a pharmaceutically acceptable inorganic or organic acid including but not limited to hydrochloric, hydrobromic, sulfuric, phosphoric, methanesulfonic, toluenesulphonic, benzenesulphonic, acetic, propionic, ascorbic, citric, malonic, fumaric, maleic, lactic, salicyclic, sulfamic, or tartartic acids. The counter ion of quarternary amines and pyridiniums include chloride, bromide, iodide, sulfate, phosphate, methansulfonate, citrate, acetate, malonate, fumarate, sulfamate, and tartate. The base addition salts include but are not limited to salts such as sodium, potassium, calcium, lithium, magnesium, ammonium and alkylammonium. Also, basic nitrogen-containing groups may be quaternised with such agents as lower alkyl halides, such as methyl, ethyl, propyl, and butyl chlorides, bromides and iodides; dialkyl sulfates like dimethyl and diethyl sulfate; and others. The salts may be made in a known manner, for example by treating the compound with an appropriate acid or base in the presence of a suitable solvent.

The compounds of the invention may be in crystalline form or as solvates (e.g. hydrates) and it is intended that both forms be within the scope of the present invention. The term “solvate” is a complex of variable stoichiometry formed by a solute (in this invention, a compound of the invention) and a solvent. Such solvents should not interfere with the biological activity of the solute. Solvents may be, by way of example, water, ethanol or acetic acid. Methods of solvation are generally known within the art.

The term “pro-drug” is used in its broadest sense and encompasses those derivatives that are converted in vivo to the compounds of the invention. Such derivatives would readily occur to those skilled in the art, and include, for example, compounds where a free hydroxy group is converted into an ester derivative or a ring nitrogen atom is converted to an N-oxide. Examples of ester derivatives include alkyl esters, phosphate esters and those formed from amino acids, preferably valine. Any compound that is a prodrug of a compound of the invention is within the scope and spirit of the invention. Conventional procedures for the preparation of suitable prodrugs according to the invention are described in text books, such as “Design of Prodrugs” Ed. H. Bundgaard, Elsevier, 1985.

The term “pharmaceutically acceptable ester” includes biologically acceptable esters of compound of the invention such as sulphonic, phosphonic and carboxylic acid derivatives.

Thus, in another aspect of the invention, there is provided a prodrug or pharmaceutically acceptable ester of a compound of formula I.

In another aspect of the invention, there is provided a pharmaceutical composition that comprises a therapeutically effective amount of one or more of the aforementioned anti-RSV compounds of formula I, including pharmaceutically derivatives thereof, and optionally a pharmaceutically acceptable carrier or diluent.

Unless otherwise specified the terms “treatment” or “treating”, in the context of a method or use of the invention, includes both therapeutic and prophylactic treatments.

In further aspect of the present invention, there is provided the use of a compound of formula I, its salts or pharmaceutically acceptable derivatives thereof in the preparation of a medicament for the treatment (therapeutic or prophylactic) of RSV infections.

In another aspect of the invention, there is provided a method of treating RSV by the administration of a compound of formula I, including the administration of pharmaceutically acceptable salts, or derivatives such as prodrugs of formula I, or a composition containing at least one compound of formula I, to a patient in need to treatment.

In another aspect of the invention, there is provided a method for treating mammals infected with RSV, and in need thereof, which comprises administering to said mammal a therapeutically effective amount of one or more of the aforementioned compounds of formula I or pharmaceutically acceptable derivatives thereof.

In another aspect of the invention, there is provided a method for preventing the infection of mammals with RSV, which comprises administering to said mammal a therapeutically effective amount of one or more of the aforementioned compounds of formula I, or pharmaceutically acceptable derivatives thereof.

Although the invention has been described with reference to treating RSV, and in particularly human RSV, it will be appreciated that the invention may also be useful in the treatment of other viruses of the sub-family Pneumovrinae, more particularly, the genera Pneumovirus and Metapneumovirus, more particularly animal and human strains of RSV and metapneumovirus.

In a further form of the invention there is provided a process for the production of compounds of formula I. These compounds may be prepared using the procedure outlined in the following methods.

Scheme 1 depicts a general process for manufacture of compounds of formula III. Compounds of formula III are intermediates, similar to formula I but where R₂ is H. Compounds of formula III may be prepared via appropriate starting materials of formula II. General methods for the preparation of 2-(aroyl)benzoic acids and 3-(aroyl)pyridine-2-carboxylic acids of formula II are described by Yamaguchi, M. et. al, J. Med. Chem. 1993, 36, 4052-4060 and Natsugari, H. et. al, J. Med. Chem. 1995, 38, 3106-3120.

In general, one equivalent of an appropriate keto-acid of formula II is reacted with approximately 3 equivalents of an appropriate diamine of the general formula H₂N—B—C—NH₂. The mixture is heated under reflux in an inert solvent, such as toluene or xylene, with a Dean-Stark apparatus for 3-10 h. A catalyst, such as an acid tosylate, can be used. After this time the reaction is allowed to cool and the product filtered and recrystallised from an appropriate solvent. If no precipitate forms the solvent is evaporated in-vacuo and the residue recrystallised or purified using flash chromatography or preparative HPLC.

Compounds of formula III can also be produced by the methods described in U.S. Pat. No. 4,058,529, Sulkowski, T. S., et. al, J. Org. Chem. 1967, 32, 2180-2184 and Houlihan, W. J., et. al, J. Med. Chem. 1975, 18, 182-185. Other (novel) compounds of formula I may be obtained by acylating compounds of formula III as described in Scheme 2.

In one method, two equivalents of diisopropylethylamine or triethylamine are added to one equivalent of a compound of formula III in THF at 0° C. An acid chloride, or other acylating agent, is added to the mixture and the reaction monitored by HPLC. When the reaction is complete the reaction is quenched with water and the product extracted into a suitable organic solvent and worked up according to standard methods. Similar acylation may also be carried out by reacting one equivalent of the compound of formula III with one equivalent of the appropriate acid chloride in xylene at 120° C. for 1-24 h. The reaction is then allowed to cool and the product isolated. Alternatively, compounds of formula III may be treated with approximately 2.2 equivalents of an appropriate acid chloride or anhydride in pyridine at approximately −5° C. The mixture is allowed to arm to room temperature and after stirring for 2-24 h the product is isolated by standard methods. Acylation may also be achieved by treating the appropriate compound of formula III with the appropriate carboxylic acid (3 equivalents), TFFH (3.3 equivalents) and DIEA (3.3 equivalents) in DMF and heating to 45° C. for approximately 14 days. After this time the product is isolated by standard methods.

N-alkylated and N-sulfonylated compounds of Formula I are best obtained using suitable N-substituted diamines. These may be prepared by known methods for example that described by Kruse L. I., et. al, J. Med. Chem. 1990, 33, 781-789.

In which R₂ is —CHR₃ or —S(O)₂R₅, as earlier defined in the summary of the invention.

Hence, the appropriate keto-acid (2 equivalents) and N-substituted diamine (1 equivalent) in chlorobenzene, toluene or xylene are placed in a flask equipped with a stirrer and Dean-Stark water separator and heated at reflux until no further water is seen to separate (1-8 h). The solvent is then removed by distillation and the residue cooled. The residue can be purified using standard methods.

Compounds of Formula I where R₂ is a urea or thiourea are prepared using the following method.

One equivalent of the appropriate compound of formula III is reacted with one equivalent of the appropriate isocyanate or isothiocyanate in THF or xylene at a temperature ranging from 20.120° C. for 1-24 h. The reaction is then allowed to cool and the product filtered, washed and generally recrystallised from an appropriate solvent. If no precipitate is formed the product can be purified using standard chromatographic methods.

Other compounds of formula I can be prepared by the addition, removal or modification of existing substituents. This could be achieved by using standard techniques for functional group inter-conversion, well known in the industry such as those described in Comprehensive organic transformations: a guide to functional group preparations by Larock R C, New York, VCH Publishers, Inc. 1989.

Examples of functional group inter-conversions are: —C(O)NR′R″ from —CO₂CH₃ by heating with or without catalytic metal cyanide, e.g. NaCN, and HNR′R″ in CH₃OH; —OC(O)R from —OH with e.g., ClC(O)R in pyridine; —NC(S)NR′R″ from —NHR with an alkylisothiocyanate or thiocyanic acid; —NRC(O)OR′ from —NHR with alkyl chloroformate; —NRC(O)NR′R″ from —NHR by treatment with an isocyanate, e.g. HN═C═O or RN═C═O; —NRC(O)R′ from —NHR by treatment with ClC(O)R′ in pyridine; —C(═NR)NR′R″ from —C(NR′R″)SR with H₃NR⁺OAc⁻ by heating in alcohol; —C(NR′R″)SR from —C(S)NR′R″ with R—I in an inert solvent, e.g. acetone; —C(S)NR′R″ (where R′ or R″ is not hydrogen) from —C(S)NH₂ with HNR′R″; —C(═NCN)—NR′R″ from —C(═NR′R″)—SR with NH₂CN by heating in anhydrous alcohol, alternatively from —C(═NH)—NR′R″ by treatment with BrCN and NaOEt in EtOH; —NR—C(═NCN)SR from —NHR′ by treatment with (RS)₂C═NCN; —NR″SO₂R from —NHR′ by treatment with CISO₂R by heating in pyridine; —NR′C(S)R from —NR′C(O)R by treatment with Lawesson's reagent [2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide]; —NRSO₂CF₃ from —NHR with triflic anhydride and base, —CH(NH₂)CHO from —CH(NH₂)C(O)OR′ with Na(Hg) and HCl/EtOH; —CH₂C(O)OH from —C(O)OH by treatment with SOCl₂ then CH₂N₂ then H₂O/Ag₂O; —C(O)OH from —CH₂C(O)OCH₃ by treatment with PhMgX/HX then acetic anhydride then CrO₃; R—OC(O)R′ from RC(O)R′ by R″CO₃H; —CCH₂OH from —C(O)OR′ with Na/R′OH; —CHCH₂ from —CH₂CH₂OH by the Chugaev reaction; —NH₂ from —C(O)OH by the Curtius reaction; —NH₂ from —C(O)NHOH with TsCl/base then H₂O; —CHC(O)CHR from —CHCHOHCHR by using the Dess-Martin Periodinane regent or CrO₃/aqH₂SO₄/acetone; —C₆H₅CHO from —C₆H₅CH₃ with CrO₂Cl₂; —CHO from —CN with SnCl₂/HCl; —CN from —C(O)NHR with PCl₅; —CH₂R from —C(O)R with N₂H₄/KOH.

During the reactions a number of the moieties may need to be protected. Suitable protecting groups are well known in industry and have been described in many references such as Protecting Groups in Organic Synthesis, Greene T W, Wiley-Interscience, New York, 1981.

The abbreviations that may be used herein, including in Schemes I-II, and experimental section are as follows unless indicated otherwise:

DCM: dichloromethane DIEA: diisopropylethylamine DMF: dimethylformamide Et: ethyl EtOAc: ethyl acetate Me: methyl MeOH: methyl alcohol MS: mass spectrometry NMR: nuclear magnetic resonance Ph: phenyl HPLC: high performance liquid chromatography TEA: triethylamine TFA: Trifluoroacetic acid TFFH: Fluoro-N,N,N″,N″-tetramethylformamidinium hexafluorophosphate THF: tetrahydrofuran TsCl: Tosyl chloride TsOH: Toluenesulphonic acid

The invention also pertains to therapeutic compositions containing at least one compound of formula I including pharmaceutical acceptable salts or prodrugs.

The compositions may further contain one or more other compounds having anti-viral activity in respect of RSV, such as Virazole, or other agents such as RespiGam or Synagis.

The compositions may further contain or be administered in combination with other drugs to treat symptoms of the disease, such as for example anti-inflammatory medicaments.

The term “composition” is intended to include the formulation of an active ingredient with conventional carriers and excipients, and also with encapsulating materials as the carrier, to give a capsule in which the active ingredient (with or without other carriers) is surrounded by the encapsulation carrier.

As will be readily appreciated by those skilled in the art, the route of administration and the nature of the pharmaceutically acceptable carrier will depend on the nature of the condition and the animal to be treated. It is believed that the choice of a particular carrier or delivery system, and route of administration could be readily determined by a person skilled in the art. In the preparation of any formulation containing the compounds care should be taken to ensure that the activity of the compound is not destroyed in the process and that the compound is able to reach its site of action without being destroyed. In some circumstances it may be necessary to protect the compound by means known in the art, such as, for example, micro encapsulation. Similarly the route of administration chosen should be such that the compound reaches its site of action.

The pharmaceutical compositions or formulations include those suitable for oral, rectal, nasal, topical (including buccal and sub-lingual), vaginal or parenteral (including intramuscular, sub-cutaneous and intravenous) administration or in a form suitable for administration by inhalation or insufflation. It is envisaged that the compositions should be provided in a form suitable for oral or nasal administration or by inhalation or insufflation.

The compounds of the invention, together with a conventional adjuvant, carrier, or diluent, may thus be placed into the form of pharmaceutical compositions and unit dosages thereof, and in such form may be employed as solids, such as tablets or filled capsules, or liquids such as solutions, suspensions, emulsions, elixirs, or capsules filled with the same, all for oral use, in the form of suppositories for rectal administration; or in the form of sterile injectable solutions for parenteral (including subcutaneous) use.

Such pharmaceutical compositions and unit dosage forms thereof may comprise conventional ingredients in conventional proportions, with or without additional active compounds or principles, and such unit dosage forms may contain any suitable effective amount of the active ingredient commensurate with the intended daily dosage range to be employed. Formulations containing ten (10) milligrams of active ingredient or, more broadly, 0.1 to one hundred (100) milligrams, per tablet, are accordingly suitable representative unit dosage forms.

The compounds of the present invention can be administrated in a wide variety of oral and parenteral dosage forms. It will be obvious to those skilled in the art that the following dosage forms may comprise, as the active component, either a compound of the invention or a pharmaceutically acceptable salt of a compound of the invention.

For preparing pharmaceutical compositions from the compounds of the present invention, pharmaceutically acceptable carriers can be either solid or liquid. Solid form preparations include powders, tablets, pills, capsules, cachets, suppositories, and dispensable granules. A solid carrier can be one or more substances which may also act as diluents, flavouring agents, solubilisers, lubricants, suspending agents, binders, preservatives, tablet disintegrating agents, or an encapsulating material.

In powders, the carrier is a finely divided solid that is in a mixture with the finely divided active component.

In tablets, the active component is mixed with the carrier having the necessary binding capacity in suitable proportions and compacted in the shape and size desired.

The powders and tablets preferably contain from five or ten to about seventy percent of the active compound. Suitable carriers are magnesium carbonate, magnesium stearate, talc, sugar, lactose, pectin, dextrin, starch, gelatin, tragacanth, methylcellulose, sodium carboxymethylcellulose, a low melting wax, cocoa butter, and the like. The term “preparation” is intended to include the formulation of the active compound with encapsulating material as carrier providing a capsule in which the active component, with or without carriers, is surrounded by a carrier, which is thus in association with it. Similarly, cachets and lozenges are included. Tablets, powders, capsules, pills, cachets, and lozenges can be used as solid forms suitable for oral administration.

For preparing suppositories, a low melting wax, such as admixture of fatty acid glycerides or cocoa butter, is first melted and the active component is dispersed homogeneously therein, as by stirring. The molten homogenous mixture is then poured into convenient sized moulds, allowed to cool, and thereby to solidify.

Formulations suitable for vaginal administration may be presented as pessaries, tampons, creams, gels, pastes, foams or sprays containing in addition to the active ingredient such carriers as are known in the art to be appropriate.

Liquid form preparations include solutions, suspensions, and emulsions, for example, water or water-propylene glycol solutions. For example, parenteral injection liquid preparations can be formulated as solutions in aqueous polyethylene glycol solution.

Sterile liquid form compositions include sterile solutions, suspensions, emulsions, syrups and elixirs. The active ingredient can be dissolved or suspended in a pharmaceutically acceptable carrier, such as sterile water, sterile organic solvent or a mixture of both.

The compositions according to the present invention may thus be formulated for parenteral administration (e.g. by injection, for example bolus injection or continuous infusion) and may be presented in unit dose form in ampoules, pre-filled syringes, small volume infusion or in multi-dose containers with an added preservative. The compositions may take such forms as suspensions, solutions, or emulsions in oily or aqueous vehicles, and may contain formulation agents such as suspending, stabilising and/or dispersing agents. Alternatively, the active ingredient may be in powder form, obtained by aseptic isolation of sterile solid or by lyophilisation from solution, for constitution with a suitable vehicle, eg. sterile, pyrogen-free water, before use.

Pharmaceutical forms suitable for injectable use include sterile injectable solutions or dispersions, and sterile powders for the extemporaneous preparation of sterile injectable solutions. They should be stable under the conditions of manufacture and storage and may be preserved against oxidation and the contaminating action of microorganisms such as bacteria or fungi.

Those skilled in the art may readily determine appropriate formulations for the compounds of the present invention using conventional approaches. Identification of preferred pH ranges and suitable excipients, for example antioxidants, is routine in the art (see for example Cleland et al, 1993). Buffer systems are routinely used to provide pH values of a desired range and include carboxylic acid buffers for example acetate, citrate, lactate and succinate. A variety of antioxidants are available for such formulations including phenolic compounds such as BHT or vitamin E, reducing agents such as methionine or sulphite, and metal chelators such as EDTA.

The solvent or dispersion medium for the injectable solution or dispersion may contain any of the conventional solvent or carrier systems for the compounds, and may contain, for example, water, ethanol, polyol (for example, glycerol, propylene glycol and liquid polyethylene glycol, and the like), suitable mixtures thereof, and vegetable oils. The proper fluidity can be maintained, for example, by the use of a coating such as lecithin, by the maintenance of the required particle size in the case of dispersion and by the use of surfactants. The prevention of the action of microorganisms can be brought about where necessary by the inclusion of various antibacterial and antifungal agents, for example, parabens, chlorobutanol, phenol, sorbic acid, thimerosal and the like. In many cases, it will be preferable to include agents to adjust osmolality, for example, sugars or sodium chloride. Preferably, the formulation for injection will be isotonic with blood. Prolonged absorption of the injectable compositions can be brought about by the use in the compositions of agents delaying absorption, for example, aluminium monostearate and gelatin. Pharmaceutical forms suitable for injectable use may be delivered by any appropriate route including intravenous, intramuscular, intracerebral, intrathecal, epidural injection or infusion.

Sterile injectable solutions are prepared by incorporating the active compounds in the required amount in the appropriate solvent with various other ingredients such as these enumerated above, as required, followed by filtered sterilization. Generally, dispersions are prepared by incorporating the various sterilised active ingredient into a sterile vehicle which contains the basic dispersion medium and the required other ingredients from those enumerated above. In the case of sterile powders for the preparation of sterile injectable solutions, preferred methods of preparation are vacuum drying or freeze-drying of a previously sterile-filtered solution of the active ingredient plus any additional desired ingredients.

When the active ingredients are suitably protected they may be orally administered, for example, with an inert diluent or with an assimilable edible carrier, or it may be enclosed in hard or soft shell gelatin capsule, or it may be compressed into tablets, or it may be incorporated directly with the food of the diet. For oral therapeutic administration, the active compound may be incorporated with excipients and used in the form of ingestible tablets, buccal tablets, troches, capsules, elixirs, suspensions, syrups, wafers, and the like. Such compositions and preparations preferably contain at least 1% by weight of active compound. The percentage of the compositions and preparations may, of course, be varied and may conveniently be between about to about 80% of the weight of the unit. The amount of active compound in therapeutically useful compositions should be sufficient that a suitable dosage will be obtained.

The tablets, troches, pills, capsules and the like may also contain the components as listed hereafter: a binder such as gum, acacia, corn starch or gelatin; excipients such as dicalcium phosphate; a disintegrating agent such as corn starch, potato starch, alginic acid and the like; a lubricant such as magnesium stearate; and a sweetening agent such a sucrose, lactose or saccharin may be added or a flavouring agent such as peppermint, oil of wintergreen, or cherry flavouring. When the dosage unit form is a capsule, it may contain, in addition to materials of the above type, a liquid carrier.

Various other materials may be present as coatings or to otherwise modify the physical form of the dosage unit. For instance, tablets, pills, or capsules may be coated with shellac, sugar or both. A syrup or elixir may contain the active compound, sucrose as a sweetening agent, methyl and propylparabens as preservatives, a dye and flavouring such as cherry or orange flavour. Of course, any material used in preparing any dosage unit form should be pharmaceutically pure and substantially non-toxic in the amounts employed. In addition, the active compound(s) may be incorporated into sustained-release preparations and formulations, including those that allow specific delivery of the active peptide to specific regions of the gut.

Aqueous solutions suitable for oral use can be prepared by dissolving the active component in water and adding suitable colorants, flavours, stabilising and thickening agents, as desired.

Aqueous suspensions suitable for oral use can be made by dispersing the finely divided active component in water with viscous material, such as natural or synthetic gums, resins, methylcellulose, sodium carboxymethylcellulose, or other well known suspending agents.

Pharmaceutically acceptable carriers and/or diluents include any and all solvents, dispersion media, coatings, antibacterial and antifungal agents, isotonic and absorption delaying agents and the like. The use of such media and agents for pharmaceutical active substances is well known in the art. Except in so far as any conventional media or agent is incompatible with the active ingredient, use thereof in the therapeutic compositions is contemplated. Supplementary active ingredients can also be incorporated into the compositions.

Also included are solid form preparations that are intended to be converted, shortly before use, to liquid form preparations for oral administration. Such liquid forms include solutions, suspensions, and emulsions. These preparations may contain, in addition to the active component, colorants, flavours, stabilisers, buffers, artificial and natural sweeteners, dispersants, thickeners, solubilising agents, and the like.

For topical administration to the epidermis the compounds according to the invention may be formulated as ointments, creams or lotions, or as a transdermal patch. Ointments and creams may, for example, be formulated with an aqueous or oily base with the addition of suitable thickening and/or gelling agents. Lotions may be formulated with an aqueous or oily base and will in general also contain one or more emulsifying agents, stabilising agents, dispersing agents, suspending agents, thickening agents, or colouring agents.

Formulations suitable for topical administration in the mouth include lozenges comprising active agent in a flavoured base, usually sucrose and acacia or tragacanth; pastilles comprising the active ingredient in an inert base such as gelatin and glycerin or sucrose and acacia; and mouthwashes comprising the active ingredient in a suitable liquid carrier.

Solutions or suspensions are applied directly to the nasal cavity by conventional means, for example with a dropper, pipette or spray. The formulations may be provided in single or multidose form. In the latter case of a dropper or pipette, this may be achieved by the patient administering an appropriate, predetermined volume of the solution or suspension. In the case of a spray, this may be achieved for example by means of a metering atomising spray pump. To improve nasal delivery and retention the compounds according to the invention may be encapsulated with cyclodextrins, or formulated with other agents expected to enhance delivery and retention in the nasal mucosa.

Administration to the respiratory tract may also be achieved by means of an aerosol formulation in which the active ingredient is provided in a pressurised pack with a suitable propellant such as a chlorofluorocarbon (CFC) for example dichlorodifluoromethane, trichlorofluoromethane, or dichlorotetrafluoroethane, carbon dioxide, or other suitable gas. The aerosol may conveniently also contain a surfactant such as lecithin. The dose of drug may be controlled by provision of a metered valve.

Alternatively the active ingredients may be provided in the form of a dry powder, for example a powder mix of the compound in a suitable powder base such as lactose, starch, starch derivatives such as hydroxypropylmethyl cellulose and polyvinylpyrrolidone (PVP). Conveniently the powder carrier will form a gel in the nasal cavity. The powder composition may be presented in unit dose form for example in capsules or cartridges of, e.g., gelatin, or blister packs from which the powder may be administered by means of an inhaler.

In formulations intended for administration to the respiratory tract, including intranasal formulations, the compound will generally have a small particle size for example of the order of to 10 microns or less. Such a particle size may be obtained by means known in the art, for example by micronisation.

When desired, formulations adapted to give sustained release of the active ingredient may be employed.

The pharmaceutical preparations are preferably in unit dosage forms. In such form, the preparation is subdivided into unit doses containing appropriate quantities of the active component. The unit dosage form can be a packaged preparation, the package containing discrete quantities of preparation, such as packeted tablets, capsules, and powders in vials or ampoules. Also, the unit dosage form can be a capsule, tablet, cachet, or lozenge itself, or it can be the appropriate number of any of these in packaged form.

It is especially advantageous to formulate parenteral compositions in dosage unit form for ease of administration and uniformity of dosage. Dosage unit form as used herein refers to physically discrete units suited as unitary dosages for the subjects to be treated; each unit containing a predetermined quantity of active material calculated to produce the desired therapeutic effect in association with the required pharmaceutical carrier. The specification for the novel dosage unit forms of the invention are dictated by and directly dependent on (a) the unique characteristics of the active material and the particular therapeutic effect to be achieved, and (b) the limitations inherent in the art of compounding such an active material for the treatment of disease in living subjects having a diseased condition in which bodily health is impaired as herein disclosed in detail.

The invention also includes the compounds in the absence of carrier where the compounds are in unit dosage form.

The amount of compound of formula I administered may be in the range from about 10 mg to 2000 mg per day, depending on the activity of the compound and the disease to be treated.

Liquids or powders for intranasal administration, tablets or capsules for oral administration and liquids for intravenous administration are the preferred compositions.

EXPERIMENTAL DATA

¹H NMR spectra were recorded on either a Bruker Avance DRX 400, AC 200 or AM 300 spectrometer. Spectra were recorded in CDCl₃, d₆-acetone, CD₃OD or d₆-DMSO using the residual solvent peak as a reference. Chemical shifts are reported on the 8 scale in parts per million (ppm) using the following conventions to assign the multiplicity: s (singlet), d (doublet), t (triplet), q (quartet) m (multiplet) and prefixed b (broad). Mass spectra (ESI) were recorded on either a Micromass Platform QMS or Finnigan LCQ Advantage spectrometer. Flash chromatography was performed on 40-63 μm silica gel 60 (Merck No. 9385). Analytical HPLC was carried out using a Waters 600 Pump, Waters 717 Autosampler and a Waters 490E UV detector. Preparative HPLC was carried out using a Gilson 322 pump with a Gilson 215 liquid handler and a HP1100 PDA detector. Both HPLC systems employed Phenomonex C8(2) columns using either acetonitrile or acetonitrile containing 0.06% TFA in water or water containing 0.1% TFA.

Method A

One equivalent of an appropriate keto-acid of formula II, is reacted with approximately 3 equivalents of an appropriate diamine of the general formula H₂N—B—C—NH₂. The mixture is heated under reflux in an inert solvent, such as toluene or xylene, with a Dean-Stark apparatus for 3-10 h. A catalyst, such as an acid tosylate, can be used. After this time the reaction is allowed to cool and the product filtered and recrystallised from an appropriate solvent. If no precipitate forms the solvent is evaporated in-vacuo and the residue recrystallised or purified using flash chromatography or preparative HPLC.

Compound 1

Compound 1 was prepared using Method A employing 2-(4-chlorobenzoyl)benzoic acid

and ethylene diamine.

¹H NMR (300 MHz, CDCl₃) δ 2.05 (bs, 1H), 3.11-3.26 (m, 2H), 3.61-3.68 (m, 1H), 3.76-3.84 (m, 1H), 7.22-7.26 (m, 1H), 7.30 (d, J=8.9 Hz, 2H), 7.42-7.48 (m, 2H), 7.62 (d, J=8.8 Hz, 2H), 7.74-7.80 (m, 1H).

MS m/z 285 ([M+H⁺]

Compound 2

Compound 2 was prepared using Method A from 2-(4-chlorobenzoyl)benzoic acid and 1,3-diaminopropane.

¹H NMR (300 MHz, CDCl₃) 1.48-1.62 (m, 2H), 2.83-2.96 (m, 1H), 2.97-3.13 (m, 2H), 4.47-4.60 (m, 1H), 7.22-7.29 (m, 1H), 7.31-7.37 (m, 2H), 7.38-7.47 (m, 2H), 7.48-7.56 (m, 2H), 7.82-7.89 (m, 1H).

MS m/z ([M+H⁺] 299

Compound 7

Compound 7 was prepared using Method A from 2-(4-chlorobenzoyl)benzoic acid and 1,4-diaminobutane.

¹H NMR (300 MHz, CDCl₃) δ 1.13-1.32 (m, 2H), 1.33-1.57 (m, 2H), 2.15-2.44 (m, 2H), 2.73-2.90 (m, 1H), 3.32-3.49 (m, 1H), 7.10-7.20 (m, 1H), 7.21-7.34 (m, 4H), 7.35-7.49 (m, 2H), 7.60-7.71 (m, 1H).

MS m/z ([M+H⁺]313

The methods for forming compounds of formula III are based on those described in U.S. Pat. No. 4,058,529, Sulkowski, T. S., et. al, J. Org. Chem. 1967, 32, 2180-2184 and Houlihan, W. J., et. al, J. Med. Chem. 1975, 18, 182-185.

Method B

Two equivalents of diisopropylethylamine or triethylamine are added to one equivalent of compound of formula III in THF at 0° C. An acid chloride, or other acylating agent, is added to the mixture and the reaction monitored by HPLC. When the reaction is complete the reaction is quenched with water and the product extracted into EtOAc. The EtOAc is subsequently washed with a 1:1 solution of sat. NH₄Cl_((aq)):water, 1:1 sat. Na₂CO_(3(aq)):water and sat. Na₂CO_(3(aq)). The EtOAc was dried (Na₂SO₄), the solvent evaporated in vacuo and the residue either crystallised or purified by flash chromatography using EtOAc/hexanes or by preparative HPLC.

Method C

One equivalent of the appropriate compound of formula II is reacted with one equivalent of the appropriate acid chloride in xylene at 120° C. for 1-24 h. The reaction is then allowed to cool and the product filtered and recrystallised from an appropriate solvent. If no precipitate is formed the reaction is purified using flash chromatography or preparative HPLC.

Method D

N-alkylated diamines may be prepared according to the procedure outlined in Kruse L. I., et. al, J. Med. Chem. 1990, 33, 781-789.

Appropriate keto-acid (2 equivalents) and N-substituted diamine (1 equivalent) in chlorobenzene, toluene or xylene are placed in a flask equipped with a stirrer and Dean-Stark water separator. The mixture is refluxed until no further water is seen to separate (1-8 h) after which time the solvent is then distilled off and the residue cooled. The residue is purified using flash chromatography or preparative HPLC.

Method E

One equivalent of the appropriate compound of formula III is reacted with one equivalent of the appropriate isocyanate or isothiocyanate in THF or xylene at a temperature ranging from 20-120° C. for 1-24 h. The reaction is then allowed to cool and the product filtered, washed and recrystallised from an appropriate solvent. If no precipitate was formed the reaction was purified using flash chromatography or preparative HPLC.

Compound 12

Compound 12 was prepared using Method C using Compound 1 and 4-fluorobenzoyl chloride.

¹H NMR (300 MHz, CDCl₃) δ 3.22-3.34 (m, 1H), 3.73-3.82 (m, 1H), 3.91-4.03 (m, 1H), 4.28-4.36 (m, 1H), 7.05-7.13 (m, 2H), 7.17 (d, J=7.8 Hz, 2H), 7.33 (d, J=7.8 Hz, 2H), 7.43-7.52 (m, 2H), 7.54-7.65 (m, 2H), 7.84-7.90 (m, 1H), 8.00-8.06 (m, 1H).

MS m/z 407 ([M+H⁺]

Compound 13

Compound 13 was prepared using Method C using Compound 1 and benzoyl chloride.

¹H NMR (300 MHz, CDCl₃) δ 3.21-3.31 (m, 1H), 3.72-3.79 (m, 1H), 3.91-4.00 (m, 1H), 4.26-4.33 (m, 1H), 7.20 (d, J=8.8 Hz, 2H), 7.34 (d, J=8.8 Hz, 2H), 7.38-7.48 (m, 5H), 7.56-7.61 (m, 2H), 7.85-7.88 (m, 1H), 8.04-8.07 (m, 1H).

MS m/z 389 ([M+H⁺]

Compound 23

Compound 23 was prepared using Method D from 2-(4-chlorobenzoyl)benzoic acid and N-benzyl ethylenediamine.

¹H NMR (300 MHz, CDCl₃) δ 2.97 (d, J_(AB) 13 Hz, 1H), 3.07-3.32 (m, 3H), 3.42 (d, J_(AB) 13 Hz, 1H), 3.83-3.96 (m, 1H), 7.04-7.09 (m, 1H), 7.17-7.38 (m, 8H), 7.39-7.46 (m, 1H), 7.66-7.73 (m, 2H), 7.81-7.86 (m, 1H).

MS m/z ([M+H⁺] 375

Compound 24

Compound 24 was prepared using Method D from 2-benzoylbenzoic acid and N-benzyl ethylenediamine.

¹H NMR (300 MHz, CDCl₃) δ 2.99 (d, J_(AB) 13 Hz, 1H), 3.10-3.29 (m, 3H), 3.44 (d, J_(AB) 13 Hz, 1H), 3.84-3.99 (m, 1H), 7.07-7.13 (m, 1H), 7.18-7.44 (m, 10H), 7.73-7.81 (m, 2H), 7.82-7.87 (m, 1H).

MS m/z ([M+H⁺]341

Compound 25

Compound 25 was prepared using Method D from 2-(4-toluoyl)benzoic acid and N-benzyl ethylenediamine.

¹H NMR (300 MHz, CDCl₃) δ 2.36 (s, 3H), 3.00 (d, J_(AB) 13 Hz, 1H), 3.11-3.29 (m, 3H), 3.45 (d, J_(AB) 13 Hz, 1H), 3.86-3.98 (m, 1H), 7.08-7.14 (m, 1H), 7.15-7.21 (m, 2H), 7.22-7.44 (m, 7H), 7.63-7.69 (m, 2H), 7.81-7.86 (m, 1H).

MS m/z ([M+H⁺]355

Compound 106

Compound 106 was prepared using Method A employing 3-bromo-(4-chlorobenzoyl)benzoic acid and ethylene diamine.

1H NMR (300 MHz, CDCl3): δ 3.12-3.25 (m, 2H), 3.64-3.71 (m, 1H), 3.76-3.83 (m, 1H), 7.13, (dd, J 8.1, 0.6 Hz, 1H), 7.33 (d, J=8.7 Hz, 2H), 7.57-7.61 (m, 3H), 7.91 (dd, J 1.8, 0.6 Hz, 1H).

MS m/z ([M+H]+) 365

Compound 107

Compound 107 was prepared using Method A employing 4-bromo-(4-chlorobenzoyl)benzoic acid and ethylene diamine.

1H NMR (300 MHz, CDCl3): δ 3.11-3.24 (m, 2H), 3.69-3.63 (m, 1H), 3.76-3.82 (m, 1H), 7.34, (d, J=8.7 Hz, 1H), 7.39 (dd, J 1.5, 0.6 Hz, 1H), 7.59-7.66 (m, 4H).

MS m/z ([M+H]+) 365

Method F

Two equivalents of boronic acid or ester, five equivalents of Na₂CO₃ and palladium on charcoal (catalytic) or 0.1 equivalents of [PdCl₂(dppf)](dichloro[1,1′-bis(diphenylphosphino)ferrocene]palladium (II) dichloromethane adduct) are added to the appropriate bromo-substituted compound of formula III in DME/H2O (93:7). The reaction is heated to 50° C. for 1-4 h. The reaction is then cooled, filtered and evaporated in vacuo to give a solid or oily residue. The residue is then either recrystallised or purified by flash chromatography using EtOAc/hexanes or by preparative HPLC.

Method G

Three equivalents of boronic acid or ester, six equivalents of K₂CO₃ and 0.3 equivalents of tetrakis(tripheynylphosphine)palladium are added to the appropriate bromo-substituted compound of formula III in toluene. The reaction is heated to 100° C. for 1-24 h. The reaction is then quenched with CH₂Cl₂ and washed with water. The CH₂Cl₂ layer was dried (Na₂SO₄) and evaporated in vacuo to give a solid or oily residue. The residue is then either recrystallised or purified by flash chromatography using EtOAc/hexanes or by preparative HPLC.

Method H

The acid chloride or anhydride or isocyanate or isothiocyanate (2.2 eq) is added directly for liquids or as a solution in pyridine (˜1M) for solids to a solution of the appropriate compound of formula III (0.1 mmol) in pyridine (500 μL) at −5° C. The reaction is stirred and allowed to warm to room temperature for between 2-24 h after which time the starting material has been consumed. The reaction is subsequently diluted with water and extracted with CH₂Cl₂ (3×). The combined CH₂Cl₂ extracts are washed with 1N NaOH (3×) and 10% HCl (3×). In the case of basic products the acid wash is omitted and in the case of acidic products the basic wash is omitted. For neutral or basic products the crude purity is improved markedly by stirring the combined CH₂Cl₂ extract in the presence of a carbonate resin (MP-Carbonate˜3 eq) for 0.5-12 h. The CH₂Cl₂ extracts are dried (MgSO₄) and the solvent evaporated in-vacuo. The crude products are subsequently purified by flash chromatography using a EtOAc/Hexane solvent system.

Compound 120

Compound 120 was prepared using Method F employing compound 107 and 4-tolylboronic acid.

1H NMR (300 MHz, CDCl₃): δ 3.19-3.26 (m, 2H), 3.65-3.72 (m, 1H), 3.86-3.89 (m, 1H), 7.23, (d, J=8.1 Hz, 2H), 7.34 (d, J=8.7 Hz, 2H), 7.39-7.45 (m, 3H), 7.65-7.71 (m, 3H), 7.82 (dd, J 8.1, 0.6 Hz, 4H).

MS m/z ([M+H]⁺) 375

Compound 132

Compound 132 was prepared using Method G employing compound 107 and n-butylboronic acid.

1H NMR (300 MHz, CDCl3): δ 0.89 (t, J=7.5 Hz, 3H), 1.23-1.37 (m, 3H), 1.48-1.56 (m, 2H), 2.59 (t, J=7.8 Hz, 2H), 3.12-3.26 (m, 2H), 3.62-3.69 (m, 1H), 3.83-3.78 (m, 1H), 7.26-7.35 (m, 3H), 7.62-7.69 (m, 3H).

MS m/z ([M+H]+) 341

Method I

A mixture of an appropriate carboxylic acid (3 eq) and TFFH (3.3 eq) was suspended in anhydrous DMF (0.25M) and DIEA (3.3 eq) under nitrogen. The mixture was heated at 45° C. for 30 min. This solution was added to the appropriate compound of Formula III (1 eq) under nitrogen and heated at 45° C. for 14 days. The reaction mixture was transferred to a 10 mL tube and diluted with CH₂Cl₂ (2 mL). The organic phase was washed with 10% citric acid (2 mL), sat. NaHCO₃ (aq) (2 mL) and evaporated to dryness. The residue was purified by flash chromatography over silica, using 0.4% methanol/CH₂Cl₂ as eluent, to isolate the desired product.

Method J

This method is an adaptation of the method described by Copéret, C. et al., J. Org. Chem., 1998, 63, 1740-1741.30% Hydrogen peroxide (100 eq) was added to a solution of either an appropriate compound of Formula I or Formula III (1 eq) and trioxorhenium 2.5 mol % in CH₂Cl₂ (4× volume of hydrogen peroxide solution) at rt. The mixture was stirred overnight after which time the mixture was diluted with water and stirred for a further 30 mins. After this time the CH₂Cl₂ was separated and the aqueous layer extracted further with CH₂Cl₂ (2×). The combined extracts were dried and the solvent evaporated in-vacuo to yield the desired product which was purified by crystallisation or chromatography as required.

Method K

An appropriate substrate of Formula I, wherein R₂=6-fluoronicotinoyl or 6-chloronicotinoyl, was produced using Method H. To this substrate was added an excess of an appropriate amine. In a suitable solvent, such as THF or ethanol, the mixture was heated in a sealed vessel to approximately 150° C. for 1-5 h (or 60° C. for 72 h in the case where the nucleophile was hydrazine). After this time the solvent was evaporated and the residue purified using flash chromatography or preparative HPLC.

Method L

A suitable phenolic compound of formula III was acylated according to Method H. Ester hydrolysis was then effected by dissolving the product in a minimal volume of methanol and treating with an excess of 1M NaOH (aq) at ambient temperature. The reaction mixture was then acidified, extracted with dichloromethane and purified by flash chromatography to yield a phenolic compound of formula I.

If desired, conversion of this phenol to a phenyl ether was then performed using standard techniques known in the industry such as those described in Vogel's Textbook of Practical Organic Chemistry by B. S. Furniss et al., Harlow, Longman Scientific & Technical, 1989 or Mitsunobu, O. Synthesis 1981, 1. The crude products were subsequently purified using flash chromatography or preparative HPLC.

Compound 239

Compound 239 was prepared from 9b-(4-hydroxyphenyl)-1,2,3,9b-tetrahydroimidazo[2,1-a]isoindol-5-one using Method L. The tetrahydroimidazoisoindolone was bis-acylated with 4-fluorobenzoyl chloride according to Method H and the resulting phenolic ester function was converted to a phenol by basic hydrolysis. The product was then treated with chloroacetonitrile and K₂CO₃ in acetone and heated to reflux for 30 h to yield phenyl ether compound 239.

¹H NMR (300 MHz, d₆-acetone) δ 3.28-3.38 (m, 1H), 3.91-3.97 (m, 1H), 4.09-4.27 (m, 2H), 5.12 (s, 2H), 7.08 (d, J=9.0 Hz, 2H), 7.17-7.26 (m, 2H), 7.30 (d, J=9.0 Hz, 2H), 7.61-7.71 (m, 4H), 7.79-7.82 (m, 1H), 8.05-8.08 (m, 1H).

Method M

This method involves nucleophilic displacement of R₂ when it represents 2-haloethanoyl. A solution or suspension of an appropriate compound of Formula I (R2=COCH2Br) (1 eq) and an appropriate amine (3 eq) were allow to stand at room temperature for 3 days. The mixture was allowed to evaporate to dryness, the residue lyophilised from 30% acetonitrile/water and the resultant crude product purified by preparative HPLC.

Method N

This method was used to prepare compound 153.

Aluminium chloride (2.88 mol) was added to a stirred suspension of 3,4-pyridine anhydride (1.31 mol) in chlorobenzene (1.2 l) at RT to give an orange suspension and heated to 110° C. for 5 h. The mixture was cooled and carefully hydrolysed with water (2 l), heated to reflux for 1 h, filtered when hot and dried to give a brown solid. The solid was suspended in water (3.5 l) and basified with 10% NaOH solution (350 ml). The resulting solution was filtered, acidified to pH=3.1 with 2N HCl. The precipitate formed was filtered and refluxed with ethanol (2 l) to give a white solid (67 g). This material was dissolved in 10% NaOH (400 ml), acidified to pH 6.3 with 2N HCl and filtered to yield 3-(4-Chloro-benzoyl)-isonicotinic acid (53 g) as a white solid.

¹H-NMR (400 MHz, DMSO-d₆) δ 7.59 (d, J=8.6 Hz, 2H), 7.68 (d, J=8.6 Hz, 2H), 7.88 (dd, J 0.7, 5.0 Hz, 1H), 8.74 (d, J=0.7 Hz, 1H), 8.93 (d, J=5.0 Hz, 1H), 13.9 (bs, 1H) ppm.

3-(4-Chloro-benzoyl)-isonicotinic acid (53 g) and ethylene diamine (67.7 ml) in xylenes (1.8 l) were refluxed for 4 h. The solution was filtered when hot and the filtrate evaporated under reduced pressure to give a yellow solid (58 g). This material was recrystallised from ethanol to give Compound 153 as a white solid (46.4 g).

¹H-NMR (400 MHz, CDCl₃) δ 2.12 (bs, 1H, NH), 3.19 (m, 1H), 3.21 (m, 1H), 3.71 (m, 1H), 3.83 (m, 1H), 7.36 (d, J=8.8 Hz, 2H), 7.63 (d, J=8.8 Hz, 2H), 7.66 (dd, J 1.1, 4.9 Hz, 1H), 8.64 (d, J=1.1 Hz, 1H), 8.79 (d, J=4.9 Hz, 1H) ppm. MS m/z ([M+H]⁺) 286

The above described methods were used to make the compounds described in tables 1 to 3 below. All compounds depicted in the tables were obtained. The tables set out a compound reference number, structure, observed mass (not calculated) and the method used to make the compound (based on correspondingly varied starting materials). The observed mass for the two compounds marked with * has not been included.

TABLE I Compounds of Formula III (Intermediates). m/z No Structure M + H⁺ Mtd 1

285 A 2

299 A 3

265 A 4

251 A 5

265 A 6

279 A 7

313 A 8

252 A 9

286 A 10

286 A 11

252 A 96

331 A 7

331 A 100

257 A 102

281 A 103

341 F 106

365 A 107

365 A 110

279 A 111

296 A 112

266 A 115

308 H 116

388 H 120

375 F 121

429 F 122

364 H 126

336 H 127

380 H 128

366 H 130

414 B 131

350 H 132

341 G 133

362 F 134

285 A 136

267 A 140

300 A 142

307 A 150

269 A 151

267 A 152

339 A 153

286 N 154

287 A 155

280 A 156

279 A 157

* A 158

330 A 159

293 A 160

293 A 161

329 A 162

286 A 163

319 A 164

320 A 165

287 A 166

282 A 167

332 A 168

332 A 169

286 A 170

280 A 171

321 A 176

437 A 177

437 A

TABLE 2 Compounds of the Invention (Formula I where A is Aryl) m/z No Structure M + H⁺ Mtd 12

407 B 13

389 B 14

404 E 15

418 E 16

341 B 17

355 B 18

397 B 19

439 B 20

381 B 21

361 B 22

526 B 23

375 D 24

341 D 25

355 D 26

389 D 27

355 D 28

369 D 29

375 D 30

409 D 31

389 D 32

393 D 33

359 D 34

373 D 35

389 D 36

355 D 37

369 D 38

407 D 39

373 D 40

387 D 41

469 C 42

515 C 43

423 D 44

421 D 45

387 D 46

401 D 47

468 D 48

403 D 49

423 C 50

403 C 51

419 C 52

473 C 53

457 C 54

495 C 55

481 C 56

431 C 57

435 C 58

439 D 59

390 C 60

373 C 61

387 C 62

486 D 64

417 C 65

397 C 66

413 C 67

433 C 68

417 C 69

437 C 70

428 C 71

448 C 72

401 C 73

421 C 74

395 C 75

415 C 76

425 C 77

445 C 79

374 C 80

374 C 81

384 E 82

398 E 83

477 E 84

497 E 85

434 E 86

414 E 87

436 E 88

416 E 89

432 E 91

365 D 94

429 B 98

453 B 99

453 B 101

379 B 104

418 B 105

463 B 108

487 C 109

551 H 114

327 H 117

321 B 118

307 B 124

335 H 125

406 H 129

562 H 135

341 H 137

379 H 138

323 L 139

484 C 143

350 H 144

407 H 145

429 H 146

455 H 147

548 H 172

447 D 173

461 C 174

501 B 175

501 B 178

412 E 179

428 E 180

448 E 181

434 E 182

414 E 183

380 H 184

411 H 185

394 H 186

463 H 187

497 H 188

410 H 189

389 L 190

427 H 191

401 H 192

335 H 193

337 H 194

403 H 195

429 H 196

492 H 197

426 H 198

384 H 199

349 H 200

415 H 201

441 H 202

349 H 203

415 H 204

441 H 205

473 C 206

456 C 207

475 C 208

421 C 209

411 I 210

510 I 211

447 I 212

433 I 213

437 I 214

369 I 215

423 I 216

395 I 217

449 I 218

415 I 219

379 I 220

367 I 221

353 I 222

383 I 223

433 I 224

395 I 225

493 I 226

357 I 227

431 I 228

470 I 229

401 I 230

390 H 231

391 H 232

417 H 233

325 H 234

453 H 235

479 H 236

387 H 237

511 H 238

447 L 239

428 L 240

428 L 241

352 I 242

481 I 243

397 I 244

442 I 245

447 I 246

384 I 247

409 I 248

455 I 249

397 I 250

367 I 251

423 I 252

405 I 253

453 I 254

443 I 255

451 I 256

509 I 257

389 L 258

447 L 259

461 L 260

456 L 261

465 L 262

479 L 263

498 L 264

479 L 265

451 L 266

446 L 267

443 L 268

445 L 269

447 L 270

454 M 271

439 M 272

439 M 273

453 M 274

447 M 275

447 M 276

467 M 277

450 M 278

455 M 279

469 M 280

447 M 281

433 M 282

490 M 283

433 M 284

433 M 285

419 M 286

409 M 287

426 M 288

469 M 289

425 M 290

419 M 291

419 M 292

420 M 293

409 M 294

469 M 295

469 M 296

469 M 297

475 M 298

408 M 299

436 M 300

475 M 301

492 M 302

425 M 303

437 M 304

467 H 305

375 H 306

408 H 307

441 H 308

417 L 309

459 L 310

431 L 311

431 L 312

424 H 313

425 H 314

392 H 315

513 H 316

444 H 317

419 K 318

445 K 319

405 K 320

448 K 321

449 K 322

473 H 323

480 H 324

478 H 325

407 H 326

379 H 327

395 H 328

429 H 329

439 H 330

424 H 331

466 H 332

486 H 333

461 H 334

396 H 335

395 H 503

489 J

TABLE 3 Compounds of the Invention (Formula I where A is Heteroaryl) m/z M + No. Structure H⁺ Mtd  63

408 C  78

408 C 123

342 H 336

408 C 337

342 H 338

388 H 339

322 H 340

409 H 341

435 H 342

343 H 343

414 H 344

408 H 345

342 H 346

434 H 347

442 H 348

468 H 349

468 H 350

376 H 351

434 H 352

424 J 353

409 H 354

343 H 355

389 H 356

323 H 357

404 H 358

452 H 359

454 H 360

408 H 361

402 H 362

336 H 363

391 H 364

425 H 365

426 H 366

455 H 367

455 H 368

409 H 369

409 H 370

409 H 371

428 H 372

418 J 373

444 J 374

352 J 375

403 H 376

483 H 377

479 H 378

450 H 379

446 H 380

441 H 381

474 H 382

395 H 383

476 H 384

464 H 385

462 H 386

412 H 387

471 H 388

472 H 389

474 H 390

488 H 391

473 H 392

409 H 393

H 394

470 H 395

517 H 396

501 H 397

451 H 398

437 H 399

493 H 400

499 H 401

465 H 402

513 H 403

425 H 404

483 H 405

471 H 406

491 H 407

449 H 408

471 H 409

473 H 410

489 H 411

493 H 412

408 H 413

380 H 414

380 H 415

408 H 416

480 H 417

501 H 418

504 H 419

500 H 420

408 H 421

408 H 422

422 H 423

456 H 424

498 H 425

450 H 426

488 H 427

502 H 428

484 H 429

470 H 430

396 H 431

396 H 432

452 H 433

473 H 434

441 H 435

491 H 436

460 H 437

476 H 438

506 H 439

474 H 440

493 H 441

426 H 442

430 H 443

508 H 444

411 H 445

476 H 446

478 H 447

446 H 448

381 H 449

440 H 450

444 H 451

471 H 452

449 H 453

425 H 454

472 H 455

391 H 456

398 H 457

474 H 458

489 H 459

430 H 460

431 H 461

465 H 462

487 H 463

457 H 464

440 H 465

487 H 466

491 H 467

462 H 468

488 H 469

487 H 470

493 H 471

507 H 472

457 H 473

488 H 474

473 H 475

516 H 476

503 H 477

487 H 478

394 H 479

491 H 480

425 J 481

392 H 482

506 J 483

397 H 484

396 H 485

437 H 486

H 487

447 H 488

435 H 489

460 H 490

* H 491

457 H 492

512 H 493

394 A 494

366 A 495

342 A 497

377 A 498

419 H 499

405 H 500

435 H 501

421 H 502

440 D

Method O: Separation of Stereoisomers by Chiral Chromatography

Selected compounds of the invention may be separated into single stereoisomers by HPLC using chromatographic columns with a chiral stationary phase. For example, the following racemic compounds were separated into enantiomers under the conditions detailed below.

Column: Chirex 3014 (Chirex (S)-VAL and (R)-NEA)) 250×10.0 mm

Detector wavelength: 220 nm

Separation of Compound 12 Mobile Phase A: Hexane Mobile Phase B: Isopropanol

Flow Rate: 4 mL/min

Isocratic Elution: 93% Mobile Phase A, 7% Mobile Phase B

Run Time: 20 mins

Column Temperature: 35° C. Injection Volume: 20 μl Separation of Compound 188 Mobile Phase A: Hexane Mobile Phase B: Isopropanol

Flow Rate: 4 mL/min

Isocratic Elution: 93% Mobile Phase A, 7% Mobile Phase B

Run Time: 26 mins

Column Temperature: 35° C. Injection Volume: 15 μl Separation of Compound 306 Mobile Phase A: Hexane Mobile Phase B: Ethanol

Flow Rate: 4 mL/min

Column Temperature: 25° C. Injection Volume: 20 μl Gradient Timetable:

% Mobile Time (min) Phase B 0 5 15 25 15 25 17 5 22 5

Separation of Compound 336 Mobile Phase A: Hexane Mobile Phase B: Isopropanol

Flow Rate: 4 mL/min

Isocratic Elution: 93% Mobile Phase A, 7% Mobile Phase B

Run Time: 50 mins

Column Temperature: 35° C. Injection Volume: 25 μl Separation of Compound 352 Mobile Phase A: Hexane Mobile Phase B: Ethanol

Flow Rate: 4 mL/min

Column Temperature: 25° C. Injection Volume: 15 μl Gradient Timetable:

% Mobile Time (min) Phase B 0 15 15 20 23 20 24 15 29 15

Separation of Compound 363 Mobile Phase A: Hexane Mobile Phase B: Isopropanol

Flow Rate: 4 mL/min

Column Temperature: 50° C. Injection Volume: 15 μl Gradient Timetable:

% Mobile Time (min) Phase B 0 17 25 35 26 17 31 17

Separation of Compound 368 Mobile Phase A: Hexane Mobile Phase B: Ethanol

Flow Rate: 4 mL/min

Column Temperature: 25° C. Injection Volume: 15 μl Gradient Timetable:

% Mobile Time (min) Phase B 0 5 15 25 24 25 25 5 30 5

Separation of Compound 381 Mobile Phase A: Hexane Mobile Phase B: Ethanol

Flow Rate: 4 mL/min

Column Temperature: 30° C. Injection Volume: 20 μl Gradient Timetable:

% Mobile Time (min) Phase B 0 3 15 20 24 20 25 3 30 3

Separation of Compound 414 Mobile Phase A: Hexane Mobile Phase B: Ethanol

Flow Rate: 4 mL/min

Isocratic Elution: 92% Mobile Phase A, 8% Mobile Phase B

Run Time: 25 mins

Column Temperature: 40° C. Injection Volume: 20 μl

TABLE 4 Separation of Enantiomers Using Chirex 3014 Column Compound Retention Time of Retention Time of Number Enantiomer A (mins) Enantiomer B (mins) 12 13.1 14.6 188 13.4 14.8 306 12.9 13.7 336 6.7 7.4 352 20.4 21.3 363 17.6 19.5 368 15.8 16.9 381 20.8 21.9 414 21.5 22.3 Column: Chiracel OD-H (250 mm×4.6 mm) IS Isocratic Elution: hexane:ethanol (70:30) Detector wavelength: 254 nm Flow rate: 0.7 ml/min

Injection Volume: 20 μl Column Temperature: 25° C.

TABLE 5 Separation of Enantiomers Using Chiracel OD-H Column Compound Retention Time of Retention Time of Number Enantiomer A (mins) Enantiomer B (mins) 153 15.4 12.4 363 89.6 55.1 414 23.8 17.6

Method P: Resolution of Compounds of Type III by Diastereomeric Salt Formation

A mixture of Compound 153 (1.0 g, 3.5 mmol) and (R)-(−)-1,1′-Binaphthyl-2,2′-diyl hydrogen phosphate (0.85 g, 2.44 mmol, 0.7 eq) in ethanol (90 ml) was refluxed until a clear solution was formed. After 15 minutes, the mixture was allowed to cool to room temperature for 1 h and then continued stirring under ice cooling for 1.5 h. The white crystalline salt was filtered, rinsed with ethanol (5 ml) and dried under suction for 30 minutes to yield 1.09 g of salt.

The white salt was suspended in water (25 ml) and basified with 10% NaOH solution (0.7 ml) to pH 11. The aqueous phase was extracted with ethyl acetate (100 ml then 2×75 ml). The combined organic extracts were washed with saturated NaCl solution, dried (MgSO₄) and concentrated to yield Compound 153B (0.49 g) as a white powder.

The (R)-(−)-1,1′-Binaphthyl-2,2′-diyl hydrogen phosphate was recovered from the acidified aqueous layer (pH 2) by extraction with ethyl acetate (2×100 ml). The combined organic phases were washed with saturated NaCl solution, dried (MgSO₄) and concentrated to afford a white powder (0.54 g).

RSV Antiviral Assays Method Q: RSV Antiviral Assay Protocol

Compounds of the invention were tested for their antiviral activity against respiratory syncytial virus. Cytopathic effect (CPE) assays were performed essentially as described in the literature (see for example Watanabe et al, J. Virological Methods, 1994, 48, 257). Serial dilutions of the test compounds were made in assay medium. HEp2 cells (1.0×10⁴ cells/well) were infected with RSV at a low multiplicity of infection (e.g. RSV A2 at an moi of 0.01) and 100 μL added to cultures assessing antiviral activity and cells without virus added to those assessing compound cytotoxicity. Assays were incubated for approximately days at 37° C. in a 5% CO₂ atmosphere. The extent of CPE was determined via metabolism of the vital dye 3-(4,5-dimethylthiaxol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). A 3 mg/ml stock of MTT was made in assay medium and 100 μL added to each well, taking the final MTT concentration to 1 mg/ml. After 2 hours incubation at 37° C., the media-MTr solution was removed and 200 L of isopropanol was added to dissolve the vital dye crystals. Plates were shaken and the absorbance read at 540 nm. The compound concentrations that inhibited CPE by 50% (EC50) and developed cytotoxicity (CC50) were calculated using an Excel curve fitting program.

Representative data for compounds of the invention against RSV A2 is show in Tables 6-8 where EC50 values lie in the ranges A: <100 ng/ml, B: 100-250 ng/ml and C: 250-1000 ng/ml.

TABLE 6 RSV A2 Antiviral Data for Compounds of Table 2 Cpd No. Activity Range 12 B 66 B 82 C 85 B 86 B 87 B 88 A 117 C 144 B 178 C 179 C 180 C 183 B 184 A 188 C 190 C 191 A 192 C 199 C 200 A 201 C 203 C 205 A 211 C 214 C 216 C 217 B 218 C 219 A 224 A 227 C 228 C 230 A 231 C 232 C 234 A 235 8 236 B 237 C 238 B 239 B 242 B 243 A 245 C 250 C 260 B 261 B 262 B 263 B 264 C 265 B 266 C 267 A 268 C 299 C 303 C 304 C 305 C 306 A 307 B 308 B 309 C 310 C 311 B 312 C 314 B 316 A 319 C 320 C 323 C 324 B 325 A 326 B 327 B 328 B 329 B 330 B 331 C 332 A 333 A 334 B 335 A

TABLE 7 RSV A2 Antiviral Data for Compounds of Table 3 Cpd No. Activity Range 336 B 344 C 351 C 352 B 358 B 360 C 361 B 363 A 364 C 366 A 367 C 368 A 369 B 370 C 371 C 372 C 377 A 379 B 381 A 382 C 385 A 386 B 387 B 391 A 392 B 394 C 395 C 397 B 398 B 399 C 401 B 404 C 405 B 406 C 408 C 409 B 412 A 413 A 414 A 415 C 416 C 420 C 421 C 422 C 423 C 430 A 431 A 434 C 436 B 437 C 438 C 441 B 442 A 444 B 445 A 448 B 449 A 450 B 453 A 454 B 455 C 456 A 457 C 458 B 461 A 462 A 463 A 464 C 465 C 467 A 468 C 474 B 480 A 481 C 482 A 483 A 484 A

TABLE 8 RSV A2 Antiviral Data for Compounds of Tables 4 and 5 (the B enantiomer) Cpd No. Activity Range  12B A 188B B 306B A 336B A 352B A 363B A 368B A 381B A 414B A

Method R: RSV Fusion Assay

Selected compounds of the invention were tested for their ability to inhibit the essential fusion processes of the respiratory syncytial virus.

Generation of RSV-F Constructs

Single-stranded synthetic DNA oligonucleotides encoding the portions of RSV A2 F glycoprotein incorporating optimal codons and without potential poly(A) addition or splice sites were generated synthetically (Mason et al, WO0242326). A membrane-anchored full-length F was generated essentially according to the method described therein and in Morton et al, Virology, 2003, 31, 275.

Syncytium Formation Assay

Fusion activity of the RSV-F constructs was measured in 293 cells essentially according to the method described in Morton et al, Virology, 2003, 311, 275. For example: cells in six well plates at approximately 80% confluency were transfected by adding plasmid DNA (2 μg/well) carrying the constructs of interest in CaPO₄ solution for 4 hours. After glycerol shock and wash, the transfected cells were trypsinized and 1.5×10⁴ cells/well added to 96-well plates containing half-log serial dilutions of the test compound. Syncytium formation was evaluated by visual inspection and quantified at 48 hours post-transfection by addition of 20 μL of CellTiter 96 One Solution (Promega) followed by incubation for 4 hours at 37° C. The colour reaction was then stopped by addition of 25 μL 10% SDS to each well and absorbance measured at 492 nm. The compound concentration that reduced absorbance relative to untreated control cultures by 50% (EC50) was calculated using an Excel curve fitting program.

Representative data for compounds of the invention is show in Table 9 where EC50 values lie in the ranges A: <750 ng/ml, B: 750-1500 ng/ml and C: 1500-2250 ng/ml.

TABLE 9 RSV Fusion Assay Data Compound Number RSV Fusion Assay EC50 12 C 16 B 66 B 336 A

Method S: RSV Cotton Rat Model

The cotton rat model was performed essentially as described in the literature (Wyde et al, Antiviral Res. 2003, 60, 221). Briefly, cotton rats weighing 50-100 g were lightly anesthetized with isoflurane and dosed orally with 100 mg/kg/day of compound or vehicle control. Viral infection followed 2 hours post-treatment in similarly anesthetized rats by intranasal instillation with approximately 1000 TCID50 of RSV A2 per animal. Four days after virus inoculation, each cotton rat was sacrificed and their lungs removed and RSV titres determined by plaque assay.

TABLE 10 RSV Cotton Rat Model Data Compound Number % Reduction of virus Control 352 68 306 72 336 96

Method T: RSV Balb/c Mouse Model

The mouse model was performed essentially as described by Clanci et al (Antimicroblal Agents and Chemotherapy. 2004, 48, 413). Briefly, eight week old female Balb/c mice were weighed, anesthetized intraperitoneally with Avertin™ and compound or vehicle administered orally 6 hours preinfection. Mice were inoculated intranasally with approximately 10000 TCID50 RSV A2 per animal. Three days after virus inoculation, each mouse was sacrificed and their lungs removed and RSV titres determined by plaque assay.

TABLE 11 RSV Balb/c Mouse Model Data Compound Number % reduction of virus control 336 80

It would be appreciated by a person skilled in the art the numerous variations and/or modifications may be made to the invention as shown the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference to any prior art in this specification is not, and should not be taken as an acknowledgment or any form or suggestion that that prior art forms part of the common general knowledge in Australia. 

1. A method for treating a mammal infected with respiratory syncytial (RSV), which comprises administering to the mammal a therapeutically effective amount of one or more compounds of formula I

or pharmaceutically acceptable salts or derivatives thereof, in the treatment of infections involving viruses of the Pneumovirinae sub-family, wherein A together with the atoms to which it is attached, forms an optionally substituted aromatic ring; linker B-C together with the atoms to which they are attached, forms an optionally substituted heterocyclic ring having from 5 to 8 ring atoms; R₁ is selected from C₁₋₁₂ alkyl, C₂₋₁₂ alkenyl, C₂₋₁₂ alkynyl, —(CH₂)_(n)C₃₋₇ cycloalkyl, —(CH₂)_(n)C₄₋₇ cycloalkenyl, —(CH₂)_(n) aryl, —(CH₂)_(n) arylC₁₋₁₂ alkyl, —(CH₂)_(n) arylC₂₋₁₂ alkenyl, —(CH₂)_(n) arylC₂₋₁₂ alkynyl, and —(CH₂)_(n) heterocyclyl; n is 0-6 and the alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl and heterocyclyl groups are optionally substituted; R₂ is selected from —CH₂R₃, —C(Y)R₃, —C(Y)OR₃, —C(Y)N(R₄)R₃, —C(Y)C₂H₂N(R₄)R₃, —C(Y)CH₂SR₃ and —S(O)_(w)R₃, where R₃ is selected from hydrogen, C₁₋₁₂ alkyl, C₂₋₁₂ alkenyl, C₂₋₁₂ alkynyl, —(CH₂)_(m) arylC₃₋₇ cycloalkyl, —(CH₂)_(m)C₄₋₇ cycloalkenyl, —(CH₂)_(m) aryl, —(CH₂)_(m) arylC₁₋₁₂ alkyl, —(CH₂)_(m) arylC₂₋₁₂ alkenyl, —(CH₂)_(m) arylC₂₋₁₂ alkynyl and —(CH₂)_(m) heterocyclyl; and when R₂ is —CH₂R₃, or —C(Y)R₃, R₃ may also be selected from —S—R₅ and —O—R₅; m is 0-6; R₄ is hydrogen or C₁₋₆ alkyl; R₅ is C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, C₃₋₇ cycloalkyl, C₄₋₇ cycloalkenyl, benzyl, aryl or heterocyclyl; w is 0, 1 or 2, and the alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl and heterocyclyl groups are optionally substituted; and X and Y are independently selected from O, S and NR₆, where R₆ is independently selected from hydrogen, lower alkyl, hydroxy and lower alkoxy.
 2. The method according to claim 1 wherein R₂ is not an unsubstituted —C₁₋₆alkyl or unsubstituted —C(O)—C₁₋₆alkyl.
 3. The method according to claim 1 wherein ring A is an optionally substituted aryl ring.
 4. The method according to claim 1 wherein ring A is an optionally substituted phenyl ring.
 5. The method according to claim 1 wherein ring A is an optionally substituted heteroaryl ring.
 6. The method according to claim 1 wherein ring A together with the atoms to which it is attached, represents an optionally substituted pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, pyrrolyl, furyl, thienyl, imidazolyl, oxazolyl or isoxazolyl ring.
 7. The method according to claim 1 wherein ring A is an optionally substituted pyridyl, pyridazinyl, pyrimidinyl or pyrazinyl ring.
 8. The method according to claim 1 wherein ring A is optionally substituted pyridyl ring.
 9. The method according to claim 1 wherein ring A is optionally substituted with one or more substituents independently selected from halo, —NH₂, NO₂, C₁₋₆ alkyl, aryl and heterocyclyl, the aryl and heterocyclyl groups optionally substituted with halo, C₁₋₆alkyl or halo substituted C₁₋₆ alkyl and, when ring A contains one or more ring nitrogens, the optional substituents include N-oxides of one or more of the ring nitrogens and pyridinium salts thereof.
 10. The method according to claim 1 wherein ring A is optionally substituted with a substituent selected from halo, alkyl, C₆H₅—CH₃—C₆H₄—, CF₃—C₆H₄—, pyridyl, NO₂ and when ring A contains one or more ring nitrogens, the optional substituent also include an N-oxide form of a ring nitrogen, and pyridinium salts thereof.
 11. The method according to claim 1 wherein ring A is not substituted.
 12. The method according to claim 1 of a compound of the formula IV

its salts, N-oxides and pharmaceutically acceptable derivatives thereof, wherein B-C, X, R₁ and R₂ are as defined in claim
 1. 13. The method according to claim 1, wherein R₂ is selected from —CH₂R₃, —C(Y)R₃, —C(Y)OR₃, —C(Y)N(R₄)R₃, —C(Y)CH₂N(R₄)R₃, —C(Y)CH₂SR₃ and —S(O)_(w)R₅, where R₃ is selected from hydrogen, —C₁₋₁₂alkyl, —C₂₋₁₂alkenyl, —C₂₋₁₂alkynyl, —(CH₂)_(m)C₃₋₇cycloalkyl, —(CH₂)_(m)C₄₋₇ cycloalkenyl, —(CH₂)_(m)aryl, —(CH₂)_(m)arylC₁₋₁₂ alkyl, —(CH₂)_(m)arylC₂₋₁₂alkenyl, —(CH₂)_(m)arylC₂₋₁₂ alkynyl, —(CH₂)_(m)heterocyclyl, and when R₂ is —CH₂R₃, or —C(Y)R₃, R₃ may also be selected from —S—R₅ and —O—R₅; m is 0-6, R₄ is hydrogen or is C₁₋₆ alkyl, R₅ is selected from C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₃₋₇cycloalkyl, C₄₋₇ cycloalkenyl, benzyl, aryl and heterocyclyl, w is 0, 1 or 2, and the alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl and heterocyclyl groups are optionally substituted with one or more substituents selected from C₁₋₆ alkyl, C₁₋₆ alkoxy, C₂₋₆ alkenyl, C₂₋₆alkynyl, halo, halo-C₁₋₆ alkyl (including CF₃), hydroxy, mercapto, nitro, cyano, NH₂, mono or di((C₁₋₆alkyl)amino, phenyl, benzyl and heterocyclyl.
 14. The method according to claim 1 wherein R₂ is —CH₂—R₃, and R₃ is —(CH₂)_(m)aryl or —(CH₂)_(m) heterocyclyl and m is 0 to 3 and the aryl or heterocyclyl ring is optionally substituted.
 15. The method according to claim 1 wherein R₂ is —COR₃ and R₃ is aryl or heterocyclyl and is optionally substituted.
 16. The method according to claim 1 wherein R₃ is optionally substituted phenyl, naphthyl, furyl, thienyl, pyrrolyl, H-pyrrolyl, pyrrolinyl, pyrrolidinyl, oxazolyl, oxadiazolyl, (including 1,2,3 and 1,2,4 oxadiazolyls) thiazolyl, isoxazolyl, furazanyl, isothiazolyl, pyrazolyl, pyrazolinyl, pyrazolidinyl, imidazolyl, imidazolinyl, triazolyl (including 1,2,3 and 1,3,4 triazolyls), tetrazolyl, thiadiazolyl (including 1,2,3 and 1,3,4 thiadiazolyls), pyridyl, pyrimidinyl, pyridazinyl, pyranyl, pyrazinyl, piperidinyl. 1,4-dioxanyl, morpholinyl, 1,4-dithianyl, thiomorpholinyl, piperazinyl, 1,3,5-trithianyl, triazinyl, 1H thieno[2,3-c]pyrazolyl, thieno[2,3-b]furyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzoxazolyl, benzothiazolyl, benzisoxazolyl, benzisothiazolyl, benzimidazolyl, indazolyl, isoquinolinyl, quinolinyl, quinoxalinyl, uridinyl, purinyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, benzotriazinyl, naphthyridinyl or pteridinyl.
 17. The method according to claim 16, wherein R₃ is optionally substituted with one or more substituents selected from C₁₋₆ alkyl, C₁₋₆ alkoxy, C₂₋₆ alkenyl, C₂₋₆ alkynyl, halo, halo-C₁₋₆ alkyl (including CF₃), hydroxy, mercapto, nitro, cyano. NH₂, mono or di(C₁₋₆alkyl)amino, phenyl, benzyl and heterocyclyl.
 18. The method according to claim 1 wherein R₂ is —CON(H)R₃, and R₃ is —(CH₂)_(m) aryl or —(CH₂)_(m) heteroaryl and m is 0 to 2 and the aryl or heteroaryl ring is optionally substituted with one or more substituents independently selected from halo, lower alkyl, hydroxy, lower alkoxy and phenyl.
 19. The method according to claim 1 wherein link -B-C- is an optionally substituted link of the formula —CH₂—(CH)_(z)—, where z is 1-4.
 20. The method according to claim 19 wherein z is 1 or
 2. 21. The method according to claim 1 wherein -B-C- is a linker of the formula —CH₂CH₂—.
 22. The method according to claim 1 wherein linker -B-C- is optionally substituted no more than three optional substituents, the substituents selected from halo, lower alkyl, hydroxy, lower alkoxy, phenyl and benzyl.
 23. The method according to claim 1 wherein linker -B-C- is not substituted.
 24. The method according to claim 1 wherein X is oxygen or sulphur.
 25. The method according to claim 1 wherein R₁ is an optionally substituted aryl or heterocyclyl group.
 26. The method according to claim 1 wherein R₁ represents phenyl, thienyl, pyrrolyl, pyridyl ring or a —C₁₋₆ alkylphenyl group, the rings being optional substituted with halo, hydroxy, nitro, —NR′R″ (where R′ and R″ are independently selected from hydrogen, lower alkyl and —C(O)R, where R is C₁₋₆ alkyl, phenyl or heterocyclyl), C₁₋₁₂alkyl, phenyl and —O—R_(a), where R_(a) is —C₁₋₁₂alkyl, —C₃₋₇cycloalkyl, —C₁₋₁₂alkylC₃₋₇cycloalkyl, phenyl or —C₁₋₁₂alkylphenyl; and the C₁₋₁₂alkyl, phenyl or R_(a) group may be optionally substituted with halo, —CN, —NR′R″; —CO₂R or —CONR′R″, where R, R′ and R″ are independently selected from hydrogen or lower alkyl.
 27. The method according to claim 1 wherein R₁ is phenyl optionally substituted with a substituent selected from halo, —C₁₋₆alkyl, —C₁₋₆alkylhalo, —C₁₋₆alkylCN, —OC₁₋₆alkyl, —OC₁₋₆alkylhalo, —OC₁₋₆alkylCO₂NH₂, —OC₁₋₆alkylCN, —OC₁₋₆alkylC₃₋₇cycloalkyl, —OC₁₋₆alkylC₆H₅, —OC₁₋₆alkylOCH₃, —OC₆H₅, —OC₆H₄halo, —CF₃, —OCF₃, —NR′R″ (where R′ and R″ are independently selected from hydrogen, —C(O)C₁₋₆alkyl, —C(O)C₆H₅, —C(O)CH═CHCO₂H, —C(O)C₁₋₆alkylCO₂H, —C(O)C₁₋₆alkylCO₂CH₃, —C(O)C₁₋₆alkylC₆H₅, —C(O)C₁₋₆alkylC₆H₄CH₃, —C(O)C₁₋₆alkylC₆H₄OCH₃ and —C(O)C₁₋₆alkylC₆H₄halo), —CO₂H, —CO₂C₁₋₆alkyl, —NO₂, —OH, —C₆H₅, —C₆H₄C₁₋₆alkyl, —C₆H₄halo and —OC(O)C₁₋₆alkyl.
 28. The method according to claim 1 wherein R₁ is phenyl substituted with halo, —OC₁₋₆alkyl, —OC₁₋₆alkylhalo, —OC₁₋₆alkylCO₂NH₂, —OC₁₋₆alkylCN, —OC₁₋₆alkylC₃₋₇cycloalkyl, —OC₁₋₆alkylC₆H₅ or —OC₁₋₆alkylOCH₃.
 29. The method according to claim 1 wherein R₁ is 4-chlorophenyl.
 30. A method for the treatment of infections involving respiratory syncytial viruses (RSV) by the inhibition of the virus's fusion processes by the administration of a therapeutically effective amount of a compound of formula I as defined in claim 1, or a pharmaceutically acceptable salt or derivative thereof to a patient in need to treatment.
 31. A pharmaceutical formulation for the treatment of infections involving respiratory syncytial viruses (RSV) comprising a compound of formula I as defined in claim 1, or a pharmaceutically acceptable salt or derivative thereof. 32-37. (canceled)
 38. A compound of formula I

or a salt or pharmaceutically acceptable derivative thereof, wherein A together with the atoms to which it is attached, represents an optionally substituted phenyl, pyridyl, pyridazinyl, pyrimidinyl or pyrazinyl ring; B-C is an optionally substituted link of the formula —CH₂—(CH)_(z)—, where z is 1-4; R₁ is selected from C₁₋₁₂ alkyl, C₂₋₁₂ alkenyl, C₂₋₁₂ alkynyl, —(CH₂)_(n)C₃₋₇ cycloalkyl, —(CH₂)_(n)C₄₋₇ cycloalkenyl, —(CH₂)_(n) aryl, —(CH₂)_(n) arylC₁₋₁₂ alkyl, —(CH₂)_(n) arylC₂₋₁₂ alkenyl, —(CH₂)_(n) arylC₂₋₁₂, alkynyl, and —(CH₂)_(n) heterocyclyl; n is 0-6 and the alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl and heterocyclyl groups are optionally substituted; R₂ is selected from —CH₂R₃, —C(Y)R₃, —C(Y)OR₃, —C(Y)N(R₄)R₃ and —S(O)_(w)R₅, where R₃ is selected from hydrogen, C₁₋₁₂ alkyl, C₂₋₁₂ alkenyl, C₂₋₁₂ alkynyl, —(CH)_(m)C₃₋₇cycloalkyl, —(CH₂)_(m)C₄₋₇ cycloalkenyl, —(CH₂)_(m) aryl, —(CH₂)_(m) arylC₁₋₁₂ alkyl, —(CH₂)_(m) arylC₂₋₁₂ alkenyl, —(CH₂)_(m) arylC₂₋₁₂ alkynyl and —(CH₂)_(m) heterocyclyl; and when R₂ is —CH₂R₃, or —C(Y)R₃, R₃ may also be selected from —S—R₅ and —O—R₅; m is 0-6; R₄ is hydrogen or C₁₋₆alkyl; R₅ is C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, C₃₋₇ cycloalkyl, C₄₋₇ cycloalkenyl, benzyl, aryl or heterocyclyl; w is 0, 1 or 2, and the alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl and heterocyclyl groups are optionally substituted, X and Y are independently selected from O, S and NR₆, where R₆ is independently selected from hydrogen, lower alkyl, hydroxy and lower alkoxy; with the provisos that when A is phenyl and R₁ is 4-chlorophenyl or unsubstituted phenyl (i) R₁ is not unsubstituted cyclopropyl, halomethyl, unsubstituted phenyl or phenyl with only halo, —CH₃ and/or —OCH₃ substituents when R₂ is COR₃; (ii) R₃ is not unsubstituted phenyl or phenyl with only halo, —CH₃, —OCH₃ and/or —C(O)OCH₂CH₃ substituents when R₂ is C(O)NHR₃; (iii) R₃ is not unsubstituted phenyl or phenyl with only halo, —CH₃, —OCH₃ and/or —C(O)OCH₂CH₃ substituents when R₂ is C(S)NHR₃; and with the provisos (iv) when A is phenyl and R₂ is CH₂R₃; R₃ is not hydrogen, unsubstituted C₁₋₆ alkyl or C₁₋₆ alkyl only substituted with NH₂, mono or di C₁₋₆ alkyl amino groups; (v) when A is phenyl and R₁ is 4-methoxyphenyl, R₂ is not CHO; (vi) when A is phenyl and R₁ is phenyl optionally substituted with only halo, C₁₋₆ alkyl and/or C₁₋₆ alkoxy and R₂ is COR₃, R₃ is not methylene substituted with NH₂, mono or di C₁₋₆ alkyl amino. N-piperidinyl or N-morpholinyl; (vii) when A is phenyl and R₁ is 3-CH₃,4-CH₃CH₂CH₂NHC(O)CH₂O-phenyl, R₂ is not —S(O)₂CH₂SO₂CH₃, —CHO, —COCH₂CH₃, —CH₂CH₂OH, —CH₂CH₂OCH₃, —CH₂CO₂C(CH₃)₃ or C₁₋₆ alkyl; (viii) when A is pyridyl and R₁ is 3-CH₃,4-CH₃CH₂CH₂NHC(O)CH₂O-phenyl, R₂ is not CH₃. 39-64. (canceled)
 65. A compound selected from the group consisting of

and salts thereof.
 66. A pharmaceutical formulation for the treatment of infections involving respiratory syncytial viruses (RSV) comprising a compound of formula I as defined in claim 38, or a pharmaceutically acceptable salt or derivative thereof.
 67. A compound of formula

or a salt thereof, wherein the pyridyl ring is optionally substituted; B-C is an optionally substituted linker of the formula —CH₂—(CH₂)_(z)—, where z is 1-4; R₁ is selected from C₁₋₁₂alkyl, C₂₋₁₂alkenyl, C₂₋₁₂alkynyl, —(CH₂)_(n)C₃₋₇cycloalkyl, —(CH₂)_(n)C₄₋₇cycloalkenyl, —(CH₂)_(n)aryl, —(CH₂)_(n)arylC₁₋₁₂alkyl, —(CH₂)_(n)arylC₂₋₁₂alkenyl, —(CH₂)_(n)arylC₂₋₁₂alkynyl, and —(CH₂)_(n)heterocyclyl; n is 0-6; and the alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl and heterocyclyl groups are optionally substituted; X is selected from O, S and NR₆, where R₆ is independently selected from hydrogen, lower alkyl, hydroxy and lower alkoxy; with the proviso that when -B-C- is —CH₂CH(CH(CH₃)₂)—, R₁ is not 3-CH₃,4-CH₃CH₂CH₂NHC(O)CH₂O-phenyl-. 68-77. (canceled)
 78. Use of a compound of formula III,

and salts thereof, wherein R₁, ring A, -B-C- and X are as defined in claim 38, as an intermediate for the production of a compound of formula I as defined in claim
 38. 79. A method of separating the enantiomers of a compound of formula III by forming diastereomeric salts of the compounds using an enantiomerically enriched chiral hydrogen phosphate. 80-82. (canceled) 